111: Basal Cell Carcinoma and Basal Cell Nevus Syndrome Flashcards
(104 cards)
What are the primary risk factors for developing Basal Cell Carcinoma (BCC)?
The primary risk factors for BCC include:
- UV radiation exposure
- Light hair and eye color
- Northern European ancestry
- Inability to tan
What are the common clinical features of Basal Cell Carcinoma (BCC)?
Common clinical features of BCC include:
- Translucency
- Ulceration
- Telangiectasias
- Presence of a rolled border
What is the most common subtype of Basal Cell Carcinoma (BCC) and its characteristics?
The most common subtype of BCC is Nodular BCC. Characteristics include:
- Occurs on sun-exposed areas of the head and neck
- Appears as a translucent papule or nodule
- Usually has telangiectasias and often a rolled border
- Larger lesions with central necrosis are referred to as rodent ulcers.
What is the significance of the Sonic Hedgehog (SHH) signaling pathway in Basal Cell Carcinoma (BCC)?
The Sonic Hedgehog (SHH) signaling pathway is pivotal in the pathogenesis of BCC. Key points include:
- Malignant activation of this pathway is a common abnormality in BCCs.
- Common mutations that activate this pathway include loss of PTCH1 or Suppressor of Fused (SUFU) and activation of Smoothened (SMO).
- Approximately 90% of sporadic BCCs have identifiable mutations in at least one allele of PTCH1.
What are the preferred biopsy methods for diagnosing Basal Cell Carcinoma (BCC)?
The preferred biopsy methods for diagnosing BCC are:
- Shave biopsy
- Punch biopsy
How does the clinical presentation of Basal Cell Carcinoma typically manifest on the skin?
BCC typically presents as:
- Translucent papule or nodule
- Ulceration
- Telangiectasias
- Presence of a rolled border
What histological features are commonly observed in Basal Cell Carcinoma?
Common histological features of BCC include:
- Large nuclei with relatively little cytoplasm
- Absence of mitotic features
- Slit-like retraction of stroma forming tumor islands
- Peritumoral lacunae that assist in histopathologic diagnosis.
What are the top three most common subtypes of Basal Cell Carcinoma, and where do they typically occur?
The top three most common subtypes of BCC, in order of frequency, are:
1. Nodular BCC - typically occurs on the head and neck.
2. Superficial BCC - commonly found on the trunk.
3. Morpheaform BCC - also primarily located on the head and neck.
What are the histological features of Pigmented BCC?
- Approximately 75% of BCCs contain melanocytes, but only 25% contain large amounts of melanin.
- Melanocytes are interspersed between tumor cells and contain numerous melanin granules in their cytoplasm and dendrites.
- Tumor cells may contain little melanin, but numerous melanophages populate the stroma surrounding the tumor.
What is the appearance and differential diagnosis of Superficial BCC?
- Appearance: Most commonly presents as a well-demarcated erythematous patch on the trunk, resembling an isolated patch of eczema that does not respond to treatment.
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Differential Diagnoses:
- Squamous Cell Carcinoma (SCC)
- Lichenoid keratosis
- Nummular dermatitis
What are the histological characteristics of Morpheaform (Sclerosing, Infiltrative) BCC?
- Appearance: May have an ivory-white appearance and resemble a scar or morphea.
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Histology:
- Strands of tumor cells embedded within a dense fibrous stroma.
- Tumor cells are closely packed, sometimes only 1-2 cells thick.
- Strands of tumor extend deeply into the dermis, often larger than the clinical appearance.
What is the gold standard treatment for Basal Cell Carcinoma (BCC)?
- The gold standard for treatment of BCC is the removal of tumor with clear margins.
- Most effective treatments include:
- Surgery
- Radiotherapy
What are the recurrence rates for different treatment modalities for primary BCC?
Treatment Modality | Recurrence Rate |
|—————————————|—————–|
| Mohs Micrographic Surgery (MMS) | 1% |
| Standard Excision | 10% |
| Curettage and Desiccation | 7.7% |
| Radiation Therapy (XRT) | 8.7% |
| Cryotherapy | 7.5% |
What are the preferred treatments for recurrent BCC?
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MMS is preferred for:
- Recurrent BCC
- Any BCC that occurs at a site where tissue conservation is desired.
What is the significance of Mohs Micrographic Surgery (MMS) in the treatment of BCC, particularly for recurrent cases?
Mohs Micrographic Surgery (MMS) is significant in the treatment of BCC because:
- It offers superior histologic analysis of tumor margins, allowing for maximal conservation of tissue compared to standard excision.
- The recurrence rate for primary BCCs treated with MMS is only 1%, which is lower than other modalities.
How does the treatment approach differ for recurrent BCC compared to primary BCC?
The treatment approach for recurrent BCC differs from primary BCC in the following ways:
- Recurrent BCC is more likely to be relatively resistant to further treatments, necessitating more aggressive management.
A patient presents with a translucent papule on the head with telangiectasias and a rolled border. What is the most likely subtype of BCC, and what is the recommended treatment?
The most likely subtype is nodular BCC. The recommended treatment is Mohs micrographic surgery (MMS) for its superior histologic analysis and tissue conservation.
A patient with a history of BCC presents with a scar-like lesion on the face. What subtype of BCC should be suspected, and what is the preferred treatment?
The suspected subtype is morpheaform BCC, an aggressive variant. The preferred treatment is Mohs micrographic surgery (MMS).
A patient has a well-demarcated erythematous patch on the trunk that resembles eczema but does not respond to treatment. What is the likely diagnosis, and what histological features support it?
The likely diagnosis is superficial BCC. Histological features include buds of malignant cells extending into the dermis, peripheral palisading cells, and minimal dermal invasion.
A patient with a history of sun exposure presents with a hyperpigmented, translucent papule. What subtype of BCC is this, and what are the differential diagnoses?
This is pigmented BCC. Differential diagnoses include nodular melanoma and seborrheic keratosis.
A patient presents with a pink papule on the lower back. What subtype of BCC is this, and what is the differential diagnosis?
This is fibroepithelioma of Pinkus. The differential diagnosis includes acrochordon (skin tag).
A patient with a history of BCC presents with a lesion showing both basal cell and squamous cell differentiation. What subtype of BCC is this, and what histological features support it?
This is basosquamous BCC. Histological features include infiltrating jagged tongues of tumor cells and areas showing squamous intercellular bridge formation and cytoplasmic keratinization.
A patient with a history of BCC presents with a lesion on the nasofacial junction. What treatment is preferred, and why?
Mohs micrographic surgery is preferred because it is particularly useful for high-risk anatomic sites like the nasofacial junction.
A patient with a history of BCC presents with a lesion on the trunk. What subtype is most likely, and what are the histological features?
The most likely subtype is superficial BCC. Histological features include buds of malignant cells extending into the dermis and minimal dermal invasion.
