Salivary malignant tumors

Question 1

What is the most common salivary gland malignancy in children?

Answer 1

Mucoepidermoid carcinoma

Question 2

True or False. A history of radiation therapy to the head and neck is a risk factor for future development of salivary gland tumors.

Answer 2

True. A history of radiation therapy at any age and any dose increases the risk for development of salivary gland tumors.

Question 3

List the risk factors associated with salivary gland

cancer.

Answer 3

Previous radiation exposure, history of head and neck skin
cancer, Epstein-Barr virus, HIV infection, Hodgkin disease,
industrial exposure to rubber manufacturing or nickel compound, or employment in a beauty salon are risk
factors.

Question 4

What are clinical signs and symptoms of salivary gland malignancy?

Answer 4

Pain, fixed lesion, invasion of overlying skin, rapidly growing
mass, facial nerve palsy, and cervical lymphadenopathy

Question 5

True or false. In general, the best radiologic study
to evaluate a malignant salivary gland mass is CT
with contrast.

Answer 5

False. Although CT provides useful information, MRI is the
preferred imaging modality for parotid gland lesions. MRI
provides superior detail regarding invasion of surrounding
structures and type of pathology.

Question 6

True or False. FNA biopsy of salivary gland malignancies has high sensitivity but low specificity.

Answer 6

False. The sensitivity is fairly low, whereas the specificity is
quoted to be greater than 90% in most studies.

Question 7

Define the T stages for the Tumor, Node, Metastasis (TNM) classification for major salivary gland malignancies.

Answer 7

T1 ≤ 2 cm
T2 > 2 cm and ≤ 4 cm
T3 ≥ 4 cm and/or extraparenchymal extension
T4a Invades skin, mandible, ear canal, or facial nerve
T4b Invades skull base, pterygoid plates, or encases carotid artery
Data from Edge SB, Byrd DR, Compton CC, Fritz AG, Greene FL, Trotti A, eds. AJCC Cancer Staging Manual 7th Edition. New
York, NY: Springer; 2010.

Question 8

Define the N stages for the TNM classification for major salivary gland malignancies.

Answer 8

● Nx: Regional lymph nodes cannot be assessed.
● N0: No regional lymph nodes
● N1: Single ipsilateral node, 3 cm or smaller
● N2a: Single ipsilateral node 3 to 6 cm in diameter
● N2b: Multiple ipsilateral nodes; none larger than 6 cm
● N2c: Bilateral or contralateral nodes, none larger than
6 cm
● N3: Any lymph node larger than 6 cm in diameter

Question 9

Define the overall staging (I through IV) for major salivary gland malignancies.

Answer 9

● Stage I: T1N0M0
● Stage II: T2N0M0
● Stage III: T3N0M0 or T1–3N1M0
● Stage IVA: T1–3N2M0 or T4aN0–2M0
● Stage IVB: T4bN1–3M0 or T1–4N3M0
● Stage IVC: M1

Question 10

What is the incidence of malignancy in tumors of

the major salivary glands?

Answer 10

About 15 to 32% of parotid tumors are malignant, 41 to
45% of submandibular tumors are malignant, and 70 to 90%
of sublingual gland tumors are malignant.

Question 11

What is the incidence of cervical lymph node

metastasis in a primary submandibular neoplasm?

Answer 11

30%

Question 12

What is the most common histologic subtype of

malignant salivary gland tumors?

Answer 12

Mucoepidermoid carcinoma is the most common malig-
nant salivary gland tumor, followed by adenoid cystic
carcinoma, and then adenocarcinoma.

Question 13

Grading of mucoepidermoid carcinoma is critical

to prognosis and management. What is the histologic appearance of low-grade mucoepidermoid carcinoma?

Answer 13

Low-grade mucoepidermoid carcinoma is more cystic with little atypia and low mitotic activity. High grade is more solid.

Question 14

What is the prognosis of mucoepidermoid carcinoma?

Answer 14

Patients with low-grade and intermediate-grade carcinoma with no regional or distant metastases have an excellent prognosis, with 5-year survival greater than 90%. High-grade tumors have a lower 5-year survival of around 50%.

Question 15

What is the recommended treatment for low-

grade and high-grade mucoepidermoid carcinoma?

Answer 15

Low-grade carcinoma requires removal of the salivary gland
with a margin of healthy tissue, but elective neck dissection
is not necessarily required. High-grade carcinoma requires total excision and elective or therapeutic neck dissection and often adjuvant radiation.

Question 16

Describe the natural history of adenoid cystic carcinoma.

Answer 16

Adenoid cystic carcinoma is difficult to cure. Its course is
slow and prolonged; it commonly has perineural invasion at
manifestation; and despite excision, it frequently recurs.

Question 17

Which salivary gland malignancy has the highest rate of distant metastasis?

Answer 17

Adenoid cystic carcinoma. About 30% to 50% of patients develop metastasis, most commonly to the lungs.

Question 18

What are the 5- and 10-year survival rates for patients with acinic cell carcinoma?

Answer 18

Acinic cell carcinoma is a relatively low-grade cancer with a
5-year survival rate ranging from 75 to > 90% and a 10-year
survival rate ranging from 60 to 75%.

Question 19

What are the two main subtypes of malignant

mixed tumor?

Answer 19

Carcinoma expleomorphic adenoma and carcinosarcoma

rare

Question 20

True or False. With complete surgical excision, patients with salivary gland carcinosarcoma have
good long-term survival.

Answer 20

False. Death from disease often occurs within 3 years of diagnosis even with complete surgical excision.

Question 21

What is the most common presentation of carcinoma ex-pleomorphic adenoma?

Answer 21

A male patient in his 60s to 70s with a long-standing parotid
mass that suddenly increases in size over several months

Question 22

What is the most common manifestation of a polymorphous low-grade adenocarcinoma?

Answer 22

The most common initial manifestation is an asymptomatic

mass of the hard palate present for months to years.

Question 23

Describe the clinicopathologic features of polymorphous low-grade adenocarcinoma.

Answer 23

Slow growth, indolent behavior, and almost exclusively involves minor salivary glands with an infiltrative growth
pattern and perineural invasion

Question 24

What other cancer does salivary duct carcinoma

histologically resemble?

Answer 24

High-grade ductal carcinoma of the breast

Question 25

What is the most important diagnosis to rule out when squamous cell carcinoma is found in the parotid gland?

Answer 25

``` Other primary (e.g., skin) carcinomas with metastasis to the parotid must be ruled out. This situation is much more common than primary parotid squamous cell carcinoma. ```

Question 26

Which cancer most commonly metastasizes to the | parotid lymph nodes?

Answer 26

Skin cancer of the head and neck

Question 27

Although this topic is debated, what are the general indications for total parotidectomy in a patient with parotid malignancy?

Answer 27

● Benign tumors in the deep lobe ● Malignant tumors in the deep lobe ● High-grade parotid tumors, even if in superficial lobe ● Parotid malignancy with cervical lymph node metastasis ● Any tumor that metastasizes to parotid gland

Question 28

In general, what is the management of salivary gland malignancy with cervical lymph node metastasis?

Answer 28

If a parotid gland malignancy has cervical metastases, an ipsilateral modified radical or select neck dissection is recommended.

Question 29

True or False. Patients with node-negative (N0) necks and parotid malignancies < 4 cm should undergo prophylactic neck dissection.

Answer 29

False. Although the topic is debated, most of the literature shows that tumors with larger than 4-cm extraparotid tumor extension and higher-risk histologic types (undifferentiated carcinoma, squamous cell carcinoma, high-grade mucoepidermoid, adenocarcinoma not otherwise specified, carcinoma ex-pleomorphic adenoma, and salivary duct carcinoma) are the only parotid tumors that warrant prophylactic neck dissection.

Question 30

What type of neck dissection should a patient with a node-negative (N0) neck and high-grade salivary gland malignancy have?

Answer 30

In general, selective neck dissection: levels I through IV for a parotid primary and levels I through III for submandibular primaries

Question 31

What are the indications for adjuvant radiation therapy for salivary gland malignancies?

Answer 31

Adjuvant radiation is indicated in cases of advanced stage, positive margins after resection, high-grade tumor, peri- neural invasion, or bony invasion.

Question 32

What is the most common tumor type of the minor salivary glands?

Answer 32

When combining all tumor types, malignant tumors are more common than benign tumors in the minor salivary glands, with mucoepidermoid carcinoma the most common malignant tumor.