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Flashcards in Melanoma Deck (31):
1

A 55-year-old man undergoes biopsy of a pigmented lesion on the neck. Examination of a biopsy specimen shows superficial spreading of a malignant melanoma with no ulceration, 1.2-mm thickness, and less than 1 mitosis per mm2. In addition to wide local excision, which of the following is most appropriate treatment?

A) Interferon therapy
B) Radiation therapy
C) Regional lymphadenectomy
D) Sentinel lymph node biopsy
E) Observation

The correct response is Option D.

According to National Comprehensive Cancer Network guidelines, melanomas with Breslow thickness greater than 1 mm should be treated with wide local excision and sentinel lymph node biopsy.

Wide local excision alone, with no additional lymph node sampling, may be appropriate for some melanomas less than 1 mm, but additional factors such as mitotic rate and ulceration should be assessed.

Random lymph node sampling would not necessarily assess the first node in the draining basin, therefore, it is important that the sentinel lymph node be identified with techniques such as tracking of an intradermally injected radionucleotide using a handheld gamma probe and visual identification with blue dye.

In the past, melanomas with thickness between 1 and 4 mm were treated with elective lymph node dissection. Since several randomized, prospective studies failed to clearly demonstrate a survival advantage and the significant associated morbidity, sentinel lymph node biopsy has replaced this procedure.

While there are growing indications for the use of radiation therapy for skin cancers, intraoperative radiation therapy is not routinely used.

 

2

A 48-year-old right-hand–dominant man is referred for treatment of a biopsy-proven subungual malignant melanoma in situ of the right thumb. Which of the following is the most appropriate treatment?

A) Amputation to the interphalangeal joint with no reconstruction
B) Amputation to the metacarpophalangeal joint with toe-to-thumb transfer
C) Chemotherapy
D) Radiation therapy
E) Wide local excision with split-thickness skin grafting

The correct response is Option E.

While the literature lacks randomized control data, there is mounting evidence that melanoma in situ can be appropriately treated with wide local excision alone. This is associated with considerably less morbidity than amputation with or without reconstruction. Radiation therapy or chemotherapy are not appropriate treatment options for malignant melanoma in this setting.

 

3

A 2-month-old female infant is evaluated because of a pigmented skin lesion on the midline lumbar region. Physical examination shows a dark brown lesion that is 10 cm in diameter with an irregular surface and coarse hairs. This patient is at increased risk for which of the following?

A) Basal cell carcinoma
B) Occult spina bifida
C) Precocious puberty
D) Renal anomalies
E) Vascular malformations

The correct response is Option B.

The lesion described is a congenital melanocytic nevus (CMN). Basal cell carcinomas are associated with nevus sebaceous. Precocious puberty is seen in congenital adrenal hyperplasia, which is associated with generalized hyperpigmentation most apparent in the areolas and genitalia. Renal anomalies and vascular malformations are not associated with CMN. Abnormalities of the vertebral column including spina bifida are seen with CMN overlying the spine. These lesions are also associated with neurocutaneous melanosis.

4

A 67-year-old man with a large lentigo maligna on the left cheek comes to the office for closure after undergoing excision. Which of the following steps is most appropriate for the surgeon prior to performing a cervical-facial rotation flap?

A) Await permanent pathology results
B) Confirm negative margins by Mohs micrographic surgery
C) Evaluate the margins clinically with a Wood lamp
D) Perform confocal microscopy
E) Refer the patient for sentinel node biopsy

The correct response is Option A.

Lentigo maligna is a slow-growing lesion with a substantial radial growth pattern before progressing to invasion in most cases. These lesions often occur in the head and neck region of older patients with a history of sun exposure. Clinical occurrence is variable, but many appear as irregular, sometimes extensive, pigmented patches on the face. Staging of these lesions follows the American Joint Committee on Cancer guidelines, and prognosis is based on depth of invasion. Need for sentinel node biopsy is based on staging and is independent of resection size.

Wide local excision of the lesion is the current standard of care, but the surgical margin for successful excision remains controversial. Alternative techniques have been investigated to improve the 8 to 20% recurrence rates associated with standard excision with 5-mm margins. Mohs micrographic surgery shows promise in the treatment of this disease, but there remains difficulty in interpretation of melanocyte proliferation on frozen section, leading to the proposal of modifications of the procedure, including sending the final Mohs margins for rush permanent section evaluation for verification of clear margins, the so-called “slow Mohs.”

Clinical evaluation of margins with Wood lamp may be useful in evaluating the clinical extent of the lesion but is not adequate for determination of surgical margins. Confocal microscopy is a new technique that allows examination of melanocytes without biopsy. This modality may be useful in diagnosis of lentigo maligna, but availability is currently limited and requires training in interpretation of images.

5

An 89-year-old man comes to the office because of a 2-year history of a pigmented lesion of the left cheek. The patient has an extensive history of sun exposure but no history of skin malignancy. On examination, the lesion is flat and light brown with irregular borders, but has no nodularity or ulceration. Examination of a specimen obtained on punch biopsy shows lentigo maligna. Which of the following is the most appropriate treatment?

A) Cryotherapy with liquid nitrogen
B) External beam radiation
C) Laser ablation
D) Resection with 1-cm margins
E) Topical treatment with imiquimod

The correct response is Option D.

Lentigo maligna is melanoma in situ that primarily occurs in elderly patients with a history of extensive sun exposure. It represents 4 to 15% of all melanomas and is slow-growing in a radial phase, but can progress to lentigo maligna melanoma with invasion and metastatic potential.

Surgical resection remains the standard of care for treatment of lentigo maligna. In 1992, the National Institutes of Health Consensus Conference on Melanoma recommended a 5-mm margin for excision of lentigo maligna. However, the use of 5-mm margins has been associated with recurrence rates of 8 to 20%. In 2008, the National Cancer Comprehensive Network released guidelines indicating that 5-mm margins may be inadequate for treatment of lentigo maligna. The use of a staged excision technique has shown that 10-mm margins or greater were required in a majority of patients and resulted in low (1.7%) recurrence rates at 2 years.

Nonsurgical modalities have been investigated in the treatment of this lesion, as they tend to occur in elderly patients who may not be surgical candidates. Nonsurgical treatments are associated with recurrence rates of 20 to 100%, with laser ablation associated with the highest recurrence rates. Topical imiquimod has shown promise, but data is limited, and long-term cure rates are unknown at this point.

6

An 88-year-old woman comes to the office because of the 2-cm pigmented lesion on the vertex of the scalp shown. There is no evidence of cervical or suboccipital lymphadenopathy. Examination of a specimen obtained on punch biopsy shows a Breslow thickness of 2.1 mm, Clark Level IV, two mitotic figures per high-power field, and no evidence of ulceration. Which of the following is the most appropriate management?

A) Excision with 1-cm margins and bilateral cervical lymphadenectomy
B) Excision with 2-cm margins and delayed sentinel lymph node biopsy
C) Excision with 3-cm margins and bilateral cervical lymphadenectomy
D) Preoperative lymphoscintigraphy, excision with 1-cm margins, and immediate sentinel lymph node biopsy
E) Preoperative lymphoscintigraphy, excision with 2-cm margins, and immediate sentinel lymph node biopsy

Q image thumb

The correct response is Option E.

In the patient described with an intermediate thickness tumor (1–4 mm) and clinically negative neck, the most appropriate treatment is wide excision with 2-cm margins (shown) and a concurrent sentinel lymph node biopsy. The defect may be reconstructed with a local flap or skin graft depending on patient and surgeon preference. In Stage I and II melanomas (localized disease T1-4, and no evidence of regional lymphadenopathy, N0), Breslow tumor thickness is the most important predictor of local recurrence, regional/distant metastases, and overall survival.

Current recommended excisional margins are 0.5 to 1.0 cm for melanoma in situ/lentigo maligna. For invasive lesions less than 1 mm thick, a 1-cm margin is adequate. Lesions with Breslow thickness of 1 to 2 mm should be resected with a 1- to 2-cm margin, using closer to 2 cm when the anatomical area is more forgiving (scalp/trunk), the thickness approaches 2 mm, or the lesion displays more aggressive histopathologic features, such as ulceration, lymphovascular invasion, tumor regression, or a mitotic index greater than one figure per high-power field. Lesions between 2 to 4 mm are adequately treated with 2-cm margins. Balch, et al., have shown that 2-cm margins are safe for lesions of intermediate thickness with equivalent survival rates, less use of skin grafting, shorter hospital stays, and lower medical costs when compared with more aggressive peripheral margins. When possible, 3-cm margins should be used for tumors greater than 4 mm thick because of their high local recurrence rate (greater than 20%).

Patients with intermediate-thickness melanomas have a 20 to 25% chance of microscopic regional disease. Before the advent of sentinel lymph node biopsy, elective lymphadenectomy (ELD) was advocated for patients with intermediate-thickness melanoma because of a significant improvement in overall survival at 10 years. The primary disadvantage of routine ELD, however, was that approximately 75 to 80% of patients underwent an unnecessary procedure.

The status of the sentinel lymph node is a powerful predictor of survival in melanoma because it identifies (1) those patients with a relatively favorable prognosis requiring no further therapy; and (2) high-risk patients who might benefit from additional surgery (completion lymphadenectomy) and interferon. Current indications for sentinel lymph node biopsy include all of the following: male patients with truncal melanoma less than 0.76 mm thick (9% incidence of nodal metastasis); all patients with melanoma thickness 0.76 to 1.0 mm (5% incidence of nodal metastasis); male patients with “thin” melanomas with aggressive features (Clark Level III or greater, ulcerated, evidence of regression, or axial location; these patients have a 10% risk of metastasis); and all melanomas greater than 1 mm in thickness.

In the scenario described, 1-cm margins would be too narrow. A 3-cm margin is excessive for the lesion described. As noted, elective lymphadenectomy has been replaced with sentinel lymph node biopsy in a clinically negative neck. Finally, sentinel lymph node biopsy should be performed at the time of the primary tumor resection if possible due to variations in the lymphatic drainage that may occur after wide excision, skin grafting, or flap closure.

 

7

A 40-year-old, right-hand-dominant man comes to the office because of a 2-mm pigmented lesion beneath the thumbnail of the left hand. He says that he first noticed the lesion within the last week. The patient recalls no trauma to the thumb. He has no other fingernails or toenails with similar streaking. Biopsy of a subungual lesion is most appropriate after which of the following periods of time has passed without change?

A) 0 to 3 Weeks
B) 4 to 6 Weeks
C) 7 to 9 Weeks
D) 10 to 12 Weeks
E) 13 to 15 Weeks

The correct response is Option B.

The prognosis for a subungual melanoma is worse than that of cutaneous melanoma. Often, there is a delay in the diagnosis of subungual melanomas; in practice, it is better to be highly suspicious of any pigmented lesion beneath the nail and perform a biopsy. According to recent research, the 5-year survival rate for a patient with a subungual melanoma ranges from 28 to 30%. The 10-year survival rate drops to 0 to 13%. Clearly, this is a devastating disease, and over-vigilance regarding diagnosis is recommended. The current recommendation is to perform a biopsy of any subungual lesion after 4 to 6 weeks without significant change.

 

8

A healthy 8-year-old girl is brought to the office because of a 15-cm congenital nevus of the buttock and thigh. Which of the following is the most appropriate recommendation to the parents for management?

A ) Alexandrite laser treatment
B ) Punch biopsy
C ) Serial excision starting at age 21 years
D ) Tissue expansion and excision
E ) Observation for 3 to 6 months

The correct response is Option D.

While the overall lifetime risk of congenital nevomelanocytic lesions is estimated in the 5 to 12% range, giant nevi tend to transform earlier. Some studies suggest that 50% of the malignancies that do develop in large nevi do so by age 3 years, and 70% occur by puberty. Giant nevi are classified as lesions over 20 cm in adults, or lesions in children that are estimated to reach 20 cm by full growth (9 cm on the head, 6 cm on the body). Patients with giant congenital nevi are estimated to have a 51% increased risk of developing melanoma. Another study showed a 5-year malignant melanoma transformation rate of 5.1%.

Given this propensity for malignant transformation, many authors advocate early aggressive treatment of giant nevi, starting at age 6 months. Serial excision, skin grafting, cultured epidermal autografts, and dermal regeneration templates (Integra) have all been described as treatments. In older patients, rotation and free flaps can be incorporated as needed.

Alexandrite lasers have not been advocated for nevi. Studies of ruby and carbon dioxide lasers have mixed results, some showing adequate lesion destruction and cosmesis, others with high rates of hypertrophic scarring.

Observation may be appropriate for smaller congenital nevi, though in this patient, at this age, the melanoma risk is sufficient to warrant intervention. Over 3 to 6 months, one would not expect clinically significant changes. Indeed, many would have urged earlier treatment. Waiting until age 21 years would also be inadvisable.

Punch biopsy is useful for surveillance of smaller lesions, though it may not be representative of a large lesion, and could possibly yield false-negative results.

 

9

A 45-year-old woman comes to the office with a history of a 4.1-mm irregular black lesion of the left leg. Excisional biopsy was performed by her primary physician with a 1-mm margin. The pathology result reveals a 1.8-mm thick ulcerated malignant melanoma. A wide local excision is planned. Which of the following is the most appropriate excision margin for this lesion?

A ) 0.5-cm margin
B ) 1-cm margin
C ) 2-cm margin
D ) 3-cm margin
E ) 5-cm margin

The correct response is Option C.

The diameter of the melanoma described is not taken into account for the wide local excision that is to be performed. Wide local excision surgical margins are determined by the thickness of the tumor, not the diameter. An in situ melanoma would require a 0.5-cm margin. Melanomas with a depth of less than 1 mm (thin) require a 1-cm margin. Lesions between 1 and 4 mm (intermediate thickness) require a 2-cm margin. If the depth is greater than 4 mm (thick), a 2- to 3-cm margin is necessary. Intermediate melanomas (those of a 1- to 4-mm depth) had previously required a 4-cm margin of resection. In a landmark article in 1993, Balch, et al. recommended a 2-cm margin for intermediate-depth melanomas. Another landmark article in 1998 by Heaton, et al. advocated surgical margins of 2 cm for patients with thick melanoma.

 

10

A 60-year-old man comes to the office because of a 2-cm pigmented lesion on the right lower back (shown) that has enlarged progressively for 3 years. No lymph nodes are palpable. Examination of a specimen obtained on punch biopsy shows a Clark Level IV malignant melanoma with a Breslow thickness of 1.2 mm and ulceration. Which of the following is the most appropriate management?

A) Excision with 2-cm margins
B) Preoperative lymphoscintigraphy, sentinel lymph node biopsy, and excision with 1-cm margins
C) Preoperative lymphoscintigraphy, sentinel lymph node biopsy, and excision with 2-cm margins
D) Excision with 1-cm margins, followed by lymphoscintigraphy and sentinel lymph node biopsy at a later date
E) Excision with 3-cm margins, split-thickness skin grafting, and right axillary lymph node dissection

Q image thumb

The correct response is Option C.

A melanoma 1.2 mm in thickness on the lower back would best be excised with 2-cm margins and a concurrent sentinel lymph node biopsy. Although a few studies cite the adequacy of a 1-cm margin for tumors less than 2 mm in thickness, a punch biopsy was performed in the scenario described, and the final pathology of the complete lesion could show a thicker lesion. In a location where there is sufficient tissue, a 2-cm margin is more appropriate for a lesion that is over 1 mm in thickness. Most authors cite resection margins of 5 mm for melanoma in situ, 1 cm for melanoma less than 0.8 mm, and 2 cm for melanoma between 0.8 and 4 mm.

Patients with intermediate thickness lesions of 0.8 mm to 4 mm have a 20 to 25% incidence of microscopic regional disease. Sentinel lymphadenectomy serves to identify patients at high risk who may be candidates for adjuvant treatment. At this time, sentinel lymph node biopsy is a diagnostic, but not yet proven, therapeutic procedure.

In patients with melanomas greater than or equal to 1 mm in thickness and no clinical evidence of regional lymph node metastases, lymphoscintigraphy is performed preoperatively to define the lymphatic drainage and demonstrate sentinel lymph node location. Sentinel lymphadenectomy is performed most accurately at the time of wide and deep excision of the primary lesion. Later, sentinel lymph node localization may be impaired if the primary lesion has been excised deeply, as the drainage patterns may have been altered by the previous procedure.

It is imperative to obtain preoperative lymphoscintigraphy in areas with a high likelihood of aberrant drainage patterns. In the trunk, unpredictable drainage patterns can occur in 20 to 35% of cases.

 

11

A 65-year-old Caucasian man comes to the office because of a dark, pigmented lesion on the thumb that he first noticed 3 months ago. There is no history of trauma to the digit. Physical examination shows a variegated lesion with asymmetrical borders in the germinal matrix of the nail bed of the right thumb. Which of the following is the most appropriate first step in management? 

A ) Amputation to next joint 

B ) Radiation therapy

C ) Shave biopsy 

D ) Wide excision

E ) Observation

The correct response is Option C. 

This pigmented lesion in the patient described could be a post-traumatic subungual hematoma, benign nevus, or subungual melanoma. Benign streaks in the nail plate (melanonychia striata longitudinalis) are extremely common in African American patients and often occur spontaneously with advancing age. Similar streaking of pigment in the nail plate may reflect the presence of a benign subungual nevus of the germinal matrix. Broader streaks of variegated color and streaks with cubical pigmentation should raise suspicion of a subungual melanoma. Evaluation of a suspiciously pigmented lesion in the nail bed should commence with a shave biopsy of the lesion. A core biopsy of the germinal matrix could produce a nail bed and plate abnormality. Furthermore, there is no need for a core biopsy to determine the depth of the lesion, as the histology and staging of the nail bed are different from the skin. Wide excision or amputation is not warranted until an attempt at diagnosis has been completed. The lesion has been present for 3 months and has not grown out to the sterile matrix; because the patient says there has been no previous trauma, further observation would be inappropriate. After an injury, the nail plate and corresponding matrix grow to tip by 3 to 4 months. Radiation therapy is not appropriate without a diagnosis. 

Melanocytic hyperplasia without atypia is considered benign and can be observed. The presence of atypia or melanoma in situ requires complete excision with clear margins. The wound is closed with a full- or split-thickness nail bed graft. Acral-lentiginous melanoma is found beneath the nail, on the palm of the hand, or on the sole of the foot. These lesions represent approximately 3% of all cutaneous melanomas. The prognosis for subungual melanomas is worse than for other cutaneous melanomas, probably because of delay in diagnosis. When symptoms occur, 25 to 30% of patients have metastases. Treatment of subungual hand melanomas consists of amputation through the joint, just proximal to the lesion. Volar flaps are used for the closure of the defect. For lesions of the thumb, deepening the first space with local z-plasty is recommended to improve function. 

 

12

Which of the following additional findings in the patient shown is indicative of the most life-threatening syndrome? 
A ) Hydrocephalus 
B ) Large or multiple axial nevi 
C ) Posterior midline nevi
D ) €œSatellite € nevi 
E ) Underdevelopment of a limb

Q image thumb

The correct response is Option A.

This patient has congenital melanocytic nevi (CMN), which are birthmarks that are present at birth or become apparent within the first year of life. They are found in 1% to 2% of the general population. In addition to being cosmetically disfiguring, CMN are one of several known risk factors for development of melanoma.

While the majority of malignant melanomas arise from melanocytes in previously normal skin or within acquired and often atypical (dysplastic) melanocytic nevi, few would dispute the contention that melanomas may arise in CMN. The incidence of such malignant transformation, however, remains a highly controversial topic in cutaneous oncology. It has been estimated that large CMN carry a 4.5% to 10% lifetime risk of melanoma or other neural crest malignancies. While this risk appears to be distributed over the lifetime of the patient, recent studies suggest that it is greatest in early childhood, between birth and 10 years of age, with 50% of the malignancies developing by 5 years of age, and 70% by 10 years of age. Interestingly, 50% of the melanomas that develop occur within the nevi, but the other 50% occur within the central nervous system (CNS) or within normal skin. Despite this significant increase in risk, it should be noted that giant CMN-associated melanomas still account for less than 3% of all pediatric melanomas.

Large CMN may also be associated with symptomatic or asymptomatic systemic abnormalities. Whereas melanocytes in CMN are generally limited to the mid to upper dermis, a subset of giant CMN exhibit melanocytes in the lower third of the dermis, within the subcutaneous fat, and occasionally as deep as the fascia and skeletal muscles possibly causing ipsilateral limb underdevelopment. Large axial CMN have been associated with the syndrome of neurocutaneous melanosis (NCM).

NCM connotes the association of a large axial CMN with the CNS involvement. CNS manifestations may present as hydrocephalus, seizures, focal deficits, or partial paresis. The majority of those children with NCM who manifest such problems do so before 2 years of age. When neurologic symptoms are present, the prognosis is grave. At least two thirds of those who present with or develop symptomatic CNS disease succumb to the disease process, either because of inexorable €œbenign € proliferation of melanocytes in the leptomeninges and brain or as a result of malignant degeneration. Symptomatic hydrocephalus may necessitate the placement of a ventriculoperitoneal or ventriculojugular shunt. Unfortunately, following malignant transformation in the CNS, such shunts afford the malignant melanocytes ready access to the systemic circulation, leading to a rapid demise.

To identify which patients with CMN may have CNS involvement, a number of risk factors have been identified. These include the presence of large or multiple axial CMN or both, nevi on the posterior midline, and the presence of multiple satellite nevi. MRI with gadolinium contrast has proved to be a particularly sensitive method for detecting the presence of CNS involvement by melanocytes in such patients. MRI can detect occult neurologic involvement even in infants who are clinically normal. In addition to meningeal involvement, lesions in the cerebrum, cerebellum, spinal cord, and elsewhere have been detected. The ultimate significance of such radiologically evident lesions in clinically asymptomatic children remains to be determined. The risk of developing NCM must also be a factor in any treatment decision, as the prognosis for children with symptomatic NCM is extremely poor. Since the majority of patients with NCM will succumb to the CNS involvement and not from the nevi themselves, it may be determined that the risk of surgical removal of giant CMN in these patients outweighs the benefits.

In certain children at high risk for the development of NCM (eg, those with large CMN in a posterior axial location in the presence of satellite nevi), and especially in those children with radiologic evidence of CNS involvement, a delay in surgical treatment of the large CMN until 2 years of age (the median age for presentation of neurologic symptoms) might be considered. The prognosis for children with symptomatic CNS involvement is so poor that most are unlikely to survive long enough to succumb to the €œrelatively € low risk of cutaneous melanoma.

13

A 42-year-old man has Clark Level III melanoma with a Breslow thickness of

1.5 mm in the concha of the right ear. Physical examination shows no other palpable masses. In addition to wide excision of the lesion, which of the following is the most appropriate step in management?

A ) Infraclavicular lymph node dissection

B ) Posterior neck dissection

C ) Sentinel lymph node biopsy

D ) Superficial parotidectomy

E ) Total parotidectomy with radical neck dissection
 

The correct response is Option C.

The lymphatic drainage of the external ear is generally believed to follow its embryologic development. In general, the external auditory canal and the superior portions of the ear drain into the mastoid region and the superior cervical chain of lymph nodes. The concha and meatus are traditionally considered to drain into the parotid and/or the infraclavicular lymph nodes. However, recent studies with lymphoscintigraphy and sentinel lymph node mapping have demonstrated that lymphatic drainage can be unpredictable.

Sentinel lymph node biopsy, which also serves to stage the extent of disease, is the most appropriate management after wide excision of the lesion. It is the most specific means of identifying regional lymph node spread. The sentinel node may be located in the parotid gland, the infraclavicular node, or some other part of the cervical chain of lymph nodes.

 

14

A 9-month €‘old female infant has an 11-cm congenital melanocytic nevus. The patient is at greatest risk for malignant transformation of which of the following systems?

(A) Central nervous

(B) Endocrine

(C) Gastrointestinal

(D) Skeletal

(E) Urologic

The correct response is Option A.

Although it is difficult to assign a risk, there is an increased risk of malignant transformation in giant congenital melanocytic nevi. Studies show rates of up to 20%; however, a recent systematic review of eight large studies showed a transformation rate of 2.8% of 432 affected patients. Other estimates are between 4% and 5%.

In addition to melanoma, patients with large, congenital melanocytic nevi are at increased risk for developing neurocutaneous melanocytosis, in which collections of melanocytes are present in the leptomeninges. Malignant transformation also can occur in neurocutaneous melanosis and result in primary central nervous system (CNS) melanoma. Even without malignant transformation, neurocutaneous melanosis can carry significant morbidity and mortality, often from seizures, hydrocephalus, and other signs of CNS irritation. MRI screening of the CNS early in life is recommended for those patients who are at high risk for malignant transformation, particularly when the presentation includes a large nevus in the posterior midline and/or multiple satellite nevi. The incidence of rhabdomyosarcoma is also increased in patients with large, congenital melanocytic nevi.

15

A 45 €‘year €‘old man comes to the office because he has a one-year history of a dark streak on the nail of the thumb of the nondominant left hand. Biopsy of the specimen of involved nail bed tissue shows 1-mm-thick malignant melanoma. Which of the following is the most appropriate surgical intervention?

(A) Mohs micrographic surgery

(B) Wide soft-tissue excision

(C) Amputation at the interphalangeal joint

(D) Amputation at the mid metacarpal joint

(E) Ray amputation

The correct response is Option C.

The nail bed is unique because it is directly adherent to the underlying distal phalanx periosteum. Early studies recommended metacarpal or metacarpal ray amputations for invasive melanoma; however, recent studies have shown the efficacy of more conservative amputations without altering survival rate or local recurrence rate. Treatment goals are eradication of the tumor and preservation of function. Therefore, amputation at the level just proximal to the disease is recommended.

Pigmented lesions in the nail bed pose a significant diagnostic responsibility. Although they are almost always pigmented, their presentation could be confused with benign melanonychia striata, fungal infections, junctional nevi, warts, foreign bodies, subungual hematomas, pyogenic granuloma, and paronychia. Melanoma presenting in an advanced stage has a high mortality rate. Confirmation with biopsy is essential.

Treatment recommendations for melanoma in situ are wide soft-tissue excision with nail bed ablation and full-thickness skin grafting.

Mohs micrographic surgery is not appropriate because it is a technique to remove a tumor with minimal margins and is primarily a soft-tissue excision.

Wide soft-tissue excision does not take into account the unique anatomy of the nail bed and adherence to the underlying distal phalanx.

 

Amputation at the mid metacarpal joint and ray amputation are not appropriate because they are unnecessarily radical.

 

16

Which of the following percentages best represents the risk of transformation of a congenital giant nevus to malignant melanoma?

(A) 10%

(B) 20%

(C) 30%

(D) 40%

(E) 50%

The correct response is Option A.

Although it is generally accepted that giant congenital nevi may undergo transformation to malignant melanoma, the exact incidence is difficult to determine, due in part to limitations in methodology of the available studies. Recent reports cite an incidence ranging from 2.9% to 12.2%.

Giant congenital nevi at greatest risk for transformation to melanoma are those lesions that have a predicted largest diameter of 20 cm in adulthood. Current recommendations regarding the timing of excision are controversial, but these lesions should be removed as early as possible in childhood.

In addition to congenital melanocytic nevi, other precursor lesions that can degenerate into malignant melanoma include common acquired melanocytic nevi, dysplastic nevi, and melanoma in situ.

 

17

Which of the following skin lesions meets criteria for sentinel lymph node biopsy (SLNBx)?

(A) Basal cell carcinoma (8 cm wide) on the anterior chest

(B) Melanoma (1.6 mm thick) of the breast with bulky axillary adenopathy

(C) Melanoma €‘in €‘situ on the shoulder

(D) Squamous cell carcinoma (1.8 cm wide) on the dorsum of the hand

(E) Squamous cell carcinoma (2 cm wide) in a 26 €‘year €‘old burn scar of the foot

 

The correct response is Option E.

Sentinel lymph node biopsy (SLNBx) is a well €‘established staging procedure for melanoma and breast cancer. A patient with melanoma in situ, by definition, does not have invasion and, therefore, would not benefit from SLNBx. Conversely, the patient with bulky adenopathy most likely has regional metastatic disease and requires formal lymphadenectomy. Indications for SLNBx in non €‘melanoma skin cancers are evolving and currently include squamous cell carcinoma greater than 2 cm in diameter, Merkel cell carcinoma, and Marjolin ulcer (burn scar carcinoma). Basal cell carcinomas almost never demonstrate lymphatic spread; therefore, SLNBx would not add any diagnostic information.

 

18

A 73 €‘year €‘old man is referred to the office by his primary care physician for evaluation of discoloration of the nail of the left thumb (shown), which has been present for the past seven years. The patient says the appearance of the nail has not changed recently. Biopsy of the nail matrix shows malignant melanoma of indeterminate depth. Which of the following surgical procedures is the most appropriate management?

(A) Elective lymph node dissection and amputation at the metacarpophalangeal joint

(B) Elective lymph node dissection and nail ablation

(C) Sentinel node biopsy and amputation at the level of the interphalangeal joint

(D) Sentinel node biopsy and excision of skin with 1-cm margins

(E) Sentinel node biopsy and ray amputation of the carpometacarpal joint

 

Q image thumb

The correct response is Option C.

The annual incidence of melanoma has increased significantly from a lifetime risk of 1:1500 in 1900 to the current risk of 1:35. Nail apparatus melanomas, and specifically subungual melanomas, pose a difficult problem because they are often diagnosed late. Late diagnosis correlates with thicker melanomas and greater risk of metastasis. Approximately 20% to 25% of subungual melanomas may be amelanotic. Sentinel node biopsy has become the standard of care, and since its advent, elective lymph node dissection is no longer recommended.

Because of the proximity of the nail matrix to the periosteum and bone, adequate resection margins are not achieved with standard wide excision of 1 to 2 cm, and recommendation for excision is at the distal interphalangeal joint of the finger or interphalangeal joint of the thumb. Melanoma can track along the neurovascular bundles. Amputation at a more proximal level is not needed and does not improve prognosis. More proximal amputation also results in a critical loss of function, particularly concerning the thumb.

The presence of pigment in the paronychial area (Hutchinson sign) is shown in the photograph. An area of pigmentation in the eponychium is almost pathognomonic for subungual malignant melanoma.

 

19

A 60 €‘year €‘old man is diagnosed with melanoma of the forehead. In addition to wide local excision, in which of the following tumor stages is sentinel lymph node biopsy indicated?

(A) Tis N0 M0

(B) T2a N1 M0

(C) T2b N0 M0

(D) T3b N1 M0

(E) T4a N0 M1

 

The correct response is Option C.

Sentinel lymph node biopsy (SLNB) is the standard of care for intermediate-thickness melanoma of the trunk and extremities and is recommended when possible for intermediate melanoma of the head and neck, such as those staged T1b N0 M0. SLNB is more complicated in the head and neck because of greater variation in the lymphatic drainage systems in those areas and because of the close proximity of the primary tumor to first €‘echelon lymph nodes. However, prospective studies have reported no false negatives, and SLNB results are of great prognostic value and may be used to guide adjuvant systemic protocols. Positive sentinel lymph nodes are identified in 15% to 21% of patients, and then complete nodal dissection yields additional positive nodes in up to 20% of patients. The effect of elective lymph node dissection on patient survival rates has not been determined. Nor has local or regional control in the clinically negative neck among patients with stage I and II melanoma.

SLNB is indicated in intermediate melanoma with lymph nodes that are clinically negative. Intermediate melanoma in the head and neck includes stages IB and II. In these stages, tumor characteristics include T1b (Breslow thickness of less than 1 mm with ulceration, or Clark level of IV or V), T2 (Breslow thickness of 1.01 to 2 mm), and T3 (Breslow thickness of 2.01 to 4 mm).

A T1a tumor is a thin, less aggressive melanoma with a Breslow thickness of less than 1 mm without ulceration or a Clark level below III. Because it is not yet intermediate, this tumor is not appropriate for SLNB. A patient with an N1 tumor has a clinically positive neck, which prohibits SLNB. A T4 tumor is a deep melanoma, with a Breslow thickness of more than 4 mm. Because it is no longer intermediate, it is not appropriate for SLNB.

 

20

A 6-month-old girl is brought to the office by her parents for consultation regarding a congenital melanocytic nevus covering one third of the back. Which of the following best represents the risk of malignant transformation of this nevus?
(A) 0% to 10%
(B) 30% to 40%
(C) 60% to 70%
(D) 90% to 100%

 

The correct response is Option A.

Although difficult to assign, there is an increased risk of malignant transformation in giant congenital melanocytic nevi. Studies show rates of up to 20%; however, a recent systematic review of eight large studies showed a transformation rate of 2.8% of 432 affected patients. Other estimates are between 4% and 5%. Difficulty arises because the definition of these lesions is not standardized (large versus giant) and true long-term prospective studies are lacking. Parents of affected children, however, need counseling regarding the risks of not excising the lesions versus the extensive surgeries often required for complete resection.
 

21

A 44-year-old woman undergoes narrow-margin, complete excision of a 1-cm lesion on the right forearm that has been present for several years and has only recently begun to change in color and appearance. The pathologist reports that the central portion of the lesion contains malignant melanoma with a depth of invasion of 2.2 mm with a clear margin. Patient history, physical examination, and laboratory studies are otherwise unremarkable. In addition to reexcision, which of the following is the most appropriate management?
(A) Observation
(B) Interferon therapy
(C) Sentinel lymph node biopsy
(D) Isolated limb perfusion
(E) Axillary lymphadenectomy

The correct response is Option C.

This patient has malignant melanoma of intermediate thickness, which requires excision with a 2-cm margin and sentinel lymph node biopsy. The thickness, or depth of invasion, is the single most important determinant of melanoma=s clinical behavior. Current guidelines recommend a 1-cm margin of resection for lesions less than 1 mm in thickness. Intermediate thickness lesions (1 to 4 mm) require a 2-cm margin. Thick lesions (>4 mm) also require a 2-cm margin of resection; larger margins have not correlated with improved cure or survival.

Observation alone would result in an unacceptably high rate of local recurrence of this potentially deadly tumor.

Sentinel lymph node biopsy is advocated for intermediate thickness lesions (1 to 4 mm). Positive biopsies portend a worse prognosis, warranting complete lymphadenectomy. Routine lymphadenectomy is no longer recommended, as morbidity is high and there is no evidence of a survival benefit. Sentinel lymph node biopsy has not been shown to improve survival in patients with thick melanoma (>4 mm); these patients have high rates of local and distant metastases. Lymph node dissection is reserved for patients with clinically palpable disease.

To date, no standard adjuvant therapy has clearly increased overall survival in patients with malignant melanoma. Interferon therapy and isolated limb perfusion would not be appropriate without first establishing nodal status in this patient and are commonly reserved as treatment modalities for individuals with higher stage or recurrent disease.
 

22

A 70-year-old man is referred for evaluation of a 2.2 x 1.3-cm pigmented lesion on the right side of the neck over the midsection of the sternocleidomastoid muscle. Punch biopsy shows lentigo maligna melanoma with a Breslow thickness of 0.6 mm. Wide surgical excision with a 1-cm margin is performed. A photograph is shown above. The specimen report upgrades the Breslow thickness to 1.2 mm. Further evaluation, including CT scan of the head, neck, chest, and abdomen, shows no associated metastases. Which of the following represents the amount of additional margin of excision that is needed for adequate local management of this lesion?
(A) No additional margin is necessary
(B) 0.5 cm
(C) 2 cm
(D) 3 cm
(E) 5 cm

 

Q image thumb

The correct response is Option A.

Breslow thickness measured from the top of the granular layer to the deepest level of tumor is the single most important factor in the prognosis of melanoma. Sampling error failing to reveal the deepest point of a lesion during incisional biopsy techniques is quite common, even in experienced hands. This leads to possible need for reexcision and sometimes lymph node management. The punch biopsy either picked up a thinner area or did not include the full thickness of skin. Because of the surface extent of the lesion, a punch biopsy is still appropriate as the initial diagnostic method; however, when the entire lesion is analyzed, the thicker areas may be revealed and call into question the adequacy of the original margin of excision. In this case, no additional margin is necessary. A study performed by the World Health Organization has shown that for melanomas less than 2 mm, a surgical margin of 1 cm is just as effective as a 3-cm margin, and there is no difference in locoregional recurrence, in-transit metastases, or five-year survival rates.

Current practice recommendations advise a margin of excision of 0.5 to 1 cm for in situ melanoma. Invasive lesions with a Breslow thickness between 0 and 1 mm should have a 1-cm margin of excision. For lesions between 1 and 2 mm, a 1- to 2-cm margin is acceptable, using closer to 2 cm when the anatomic area is more forgiving, such as the trunk, or when the thickness is closer to 2 mm. Lesions between 2.1 and 4 mm should have a 2-cm margin. For lesions thicker than 4 mm, a margin of at least 2 cm should be used, but a 3-cm margin should be considered if ulceration of the tumor is present.
 

23

A 70-year-old man has a T3 N0 M0 melanoma involving the skin of the preparotid region. In addition to wide local excision and superficial parotidectomy, which of the following is the most appropriate next step in the management of the regional lymph nodes? 

(A) Observation
(B) Prophylactic radiation therapy
(C) Sentinel node biopsy
(D) Modified radical neck dissection
(E) Radical neck dissection

 

The correct response is Option C.

This patient has a T3 melanoma, which is defined as a tumor that has a Breslow’s thickness between 1.5 and 4 mm, or is designated as Clark’s level IV. Because this melanoma is of intermediate thickness and there are no palpable regional lymph nodes, it is classified as Stage II. In addition to local excision and superficial parotidectomy, sentinel node biopsy is currently recommended to rule out the presence of micrometastases in patients with these lesions. 
Lymphatic invasion has the greatest influence on prognosis, but the amount of tumor burden within the lymphatic system also affects prognosis. Approximately 30% to 40% of patients with melanomas of intermediate thickness and no palpable lymph nodes in the neck have subclinical nodal micrometastases; lymph node dissection results in increased survival in this subgroup. However, performing elective lymph node dissection in all of these patients, without identifying those who would benefit most, would subject the remaining 60% to 70% who do not have demonstrable micrometastases to unnecessary morbidity without increasing survival advantage. Sentinel lymphadenectomy using vital blue dye and radiocolloid for mapping can be performed to identify the subgroup in which regional lymphadenectomy should be performed.

Clinical observation followed by neck dissection when regional lymph nodes become apparent is not an acceptable option.

Although prophylactic radiation therapy has been shown to produce benefits similar to elective lymph node dissection in patients with tumors of intermediate thickness, it subjects approximately 66% of patients to unnecessary morbidity. As other means of identifying micrometastases become available, radiation therapy should be considered as a valid treatment alternative in selected patients.

Neck dissection is indicated for patients with stage II tumors who have micrometastases identified via sentinel lymphadenectomy and in patients who have stage III melanoma. The dissection should include levels I through V as well as any other nodal groups that may be at risk. Neck dissection has more of a staging role when it is performed in a patient with a Stage II tumor who has not undergone sentinel lymphadenectomy. A modified dissection, which spares the sternocleidomastoid muscle, internal jugular vein, and spinal accessory nerve, is often preferred. Radical neck dissection is typically performed only if these structures are involved with tumor or the surgeon is inexperienced and/or unfamiliar with the modified approach.

24

A 68-year-old man has the lesion shown in the photographs above. A satellite lesion is noted 2 cm from the primary lesion. Findings on laboratory studies and radiographs of the chest are normal. Histologic examination of a biopsy specimen of the primary tumor shows findings consistent with Clark's level IV melanoma. The tumor has a Breslow's thickness of 2.8 mm. There is no palpable adenopathy or distant metastases.

According to the American Joint Committee on Cancer, which of the following is the correct clinical classification stage of this tumor?

(A) Stage 0
(B) Stage I
(C) Stage II
(D) Stage III
(E) Stage IV

 

The correct response is Option D.

The staging of melanomas involves three descriptors: T, N, and M. The T descriptor is based on the diameter or surface area of the tumor. The N descriptor describes nodal status. The M descriptor indicates distance of metastasis beyond the neck. This staging criteria allows physicians to predict patient outcomes and choose appropriate therapy based on comparisons with patients in large studies.


This patient's tumor is classified as T4 N0 M0, or Stage III. Although earlier staging classifications placed patients with T4 tumors into a stage IIB subgroup, this has recently been changed by the American Joint Committee on Cancer because of the more aggressive behavior of melanoma and the similarity of disease outcome to other Stage III tumors.

Breslow's thickness typically takes precedence over Clark's level in the classification of melanoma; however, because this patient has a satellite lesion, which represents a more advanced level of disease, the tumor is classified as T4. Satellite lesions, defined as those lesions located within 2 cm of the primary tumor, affect tumor classification. In contrast, secondary lesions farther than 2 cm from the primary tumor are considered in-transit metastases, which influence nodal classification. The patient has not been shown to have palpable nodes or distant organ metastases; therefore, the tumor is classified as N0 and M0 respectively.

 

25

Which of the following is associated with invasive malignant melanoma?

(A) Actinic keratosis
(B) Bazex syndrome
(C) Erythroplasia of Queyrat
(D) Nevus sebaceus of Jadassohn
(E) Xeroderma pigmentosum

The correct response is Option E.

Although all of the lesions listed are premalignant, only xeroderma pigmentosum is likely to develop into invasive malignant melanoma. In patients who have this autosomal recessive condition, the skin is intolerant to ultraviolet light. Pigmentary changes result from absence of DNA repair mechanisms; affected patients develop freckling and thickening of the skin, with atrophy of the subcutaneous tissues. Malignant tumors, including melanoma, frequently develop in patients younger than 10 years. Appropriate management includes minimal sun exposure and topical sun protection.

Actinic keratoses are common premalignant lesions that occur following excessive exposure to sunlight. These lesions appear flesh colored to brown and are rough and scaly with discrete erythematous borders. If untreated, 10% of patients will develop squamous cell carcinoma. Topical application of 5-fluorouracil or surgical excision is appropriate.

Bazex syndrome is an X-linked, autosomal dominant condition that manifests as follicular atrophoderma with multiple basal cell carcinomas. Hypotrichosis and hypohidrosis are associated.

Erythroplasia of Queyrat is also known as Bowen's disease of the mucous membranes, or squamous cell carcinoma in situ. These bright red, velvety lesions affect the glans penis and prepuce, and occur less often on the vulva. Conservative excision is recommended.

Nevus sebaceus of Jadassohn is a lesion affecting the head and neck region that is present at birth and enlarges gradually. Because 10% to 15% of patients with this condition will eventually develop basal cell carcinoma, excision should be performed before the patient reaches puberty. Malignant adnexal tumors such as apocrine carcinoma occur infrequently.

 

26

An 18-month-old boy has a 25-cm pigmented lesion on his back. Which of the following is the most appropriate management?

(A) Observation with photographic mapping
(B) Intralesional injection of interferon gamma
(C) Dermabrasion
(D) Tunable dye laser ablation
(E) Excision

 

The correct response is Option E.

This 18-month-old boy has a giant congenital nevus on the back. Congenital nevi can be classified as "giant" according to several criteria, including those lesions that are larger than 20 cm in diameter, lesions that are greater than twice the size of the patient's palm, and those nevi for which excision and primary closure cannot be performed as a single procedure. Because of the potential for malignant transformation, surgical excision of the entire lesion is recommended. Although the actual risk for melanoma is controversial, one study reported that approximately 8% of patients with giant congenital nevi developed melanoma during the first 15 years after the initial appearance of the nevus.

Although observation with serial photographic mapping is advocated in patients with familial dysplastic nevus syndrome, it is not appropriate in a patient with a giant congenital nevus because of the association with malignancy. Intralesional injection of interferon gamma is indicated for patients who have confirmed malignant melanoma. Dermabrasion and laser ablation will not remove all of the immature melanocytes within the lesion. In addition, the resultant hypopigmentation seen following treatment may hinder any future monitoring for signs of malignant degeneration.

 

27

Hutchinson's freckle is another name for which of the following types of melanoma?

(A) Acral-lentiginous
(B) Lentigo maligna
(C) Mucosal
(D) Nodular
(E) Superficial spreading

 

The correct response is Option B.

Hutchinson's freckle is a misleading term for lentigo maligna melanoma, a melanoma in situ that is found within the layers of the epidermis only. This lesion typically occurs in fair-skinned, elderly persons and manifests as a macule or patch of darkened skin on the face or other sun-exposed areas. Although 5% to 10% of all melanomas can be classified as lentigo maligna, the risk for development of invasive melanoma in affected patients has been shown to range from 5% to 30% in various studies. Slow growth, often for a period of 10 to 20 years, is common initially and is then followed by an aggressive, invasive phase.

 

28

A 42-year-old woman has a pigmented matrix lesion on the index finger. Biopsy of the lesion shows a subungual melanoma. Which of the following is the most appropriate management?

(A) Ablation of the nailbed and matrix resurfacing with skin grafting
(B) Amputation at the distal interphalangeal joint
(C) Amputation at the proximal interphalangeal joint
(D) Ray amputation

 

The correct response is Option B.

This patient who has a subungual melanoma of the index finger should undergo amputation at the level of the distal interphalangeal joint. In patients with histologically confirmed subungual melanoma, the recommended level of amputation is somewhat controversial; however, conservative management (ie, amputation at the level of the joint located just proximal to the lesion) is recommended to preserve function. Ray amputation, a more aggressive alternative, is still advocated by some surgeons. Studies have reported a five-year survival rate of 66% in patients diagnosed with subungual melanoma.

This patient should undergo a complete physical examination, radiographs of the hand, and CT scans of the chest, head, abdomen, and pelvis. Although the role of elective lymph node dissection in the management of subungual melanoma is controversial, sentinel lymph node dissection may be helpful in patients who have tumors of intermediate thickness (1.0 to 4.0 mm).

Ablation of the nailbed and matrix resurfacing with skin grafting is appropriate management of melanoma in situ of the matrix, also known as melanocytic dysplasia.

 

29

A 13-year-old boy has a pigmented, slightly raised nevus on the thigh. He has no history of malignant tumors and there is no family history of melanoma. Histologic examination of an excisional biopsy specimen of the lesion shows findings consistent with juvenile melanoma; the surgical margins are free of tumor. 

Which of the following is the most appropriate next step?

(A) No additional treatment
(B) Referral to an oncologist for chemotherapy
(C) Interferon therapy
(D) Isolated limb perfusion
(E) Wide local excision

 

The correct response is Option A.

Benign juvenile melanoma is referred to by many terms, including Spitz nevus, spindle cell nevus, and epithelioid nevus. This solitary tumor is typically pink to red in color and is most likely to appear on the face in childhood. Although it can be initially mistaken for melanoma, histologic examination of a biopsy specimen will show giant spindle cells; it is believed to be a histologic variant of the compound nevus. Because it is benign, conservative treatment or complete excision is recommended. In this patient, no further treatment is required.

Chemotherapy, interferon therapy, limb perfusion, and wide excision are all options for management of malignant melanoma confirmed by histology.

 

30

A 75-year-old woman who has a discolored 4-mm lesion of the nail bed of the nondominant left thumb after undergoing removal of the nail plate for management of chronic paronychia. A biopsy specimen of the lesion shows subungual melanoma with a thickness of 3 mm. The above MRI shows possible tumor tracking along the ulnar neurovascular bundle. Lymphoscintigraphy shows two positive nodes in the axilla.

Which of the following is the most appropriate level of amputation?

(A) Carpometacarpal joint
(B) Metacarpal diaphysis
(C) Metacarpophalangeal joint
(D) Proximal phalanx diaphysis
(E) Interphalangeal joint

 

The correct response is Option D.

This patient has a subungual melanoma, an uncommon, aggressive tumor most often seen in the thumb. Excisional biopsy should be performed immediately to distinguish this type of tumor from squamous cell carcinoma, basal cell carcinoma, pyogenic granuloma, glomus tumor, or giant cell tumor. Amelanotic tumors, which are often diagnosed late, comprise approximately 30% of all subungual melanomas. A Clark's level cannot be determined in patients with subungual melanoma because of the absence of subcutaneous tissue within the nail matrix. Although in situ melanomas are associated with a relatively good prognosis, all other forms of subungual melanoma are associated with poor prognoses. The outcome is particularly poor in patients with ulcerated lesions.

Patients with melanoma must be evaluated for the presence of local, regional, and distant metastases. Consultation with a medical oncologist is needed; MRI is helpful in determining the extent of local disease. However, the MRI findings may be confused with inflammatory changes. Melanomas can extend along the neurovascular bundles.

In patients with localized subungual melanomas, amputation just proximal to the most distal joint is recommended to clear disease while maintaining length and function of the digit. Sentinel node biopsy will determine tumor staging and the need for lymphadenectomy. In order to maintain thumb function following amputation, Z-plasty, detachment of the first dorsal interosseous tendon, and a more proximal reattachment of the adductor pollicis tendon can be performed to deepen the first web space and effectively lengthen the thumb.

More distal amputation will not clear local disease and will instead increase the risk for local recurrence. A more proximal amputation will not improve the poor prognosis and will also result in a significantly less functional digit, especially when the thumb is involved.

 

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