Background Flashcards
What is the incidence of salivary cancers in the United States?
∼2,500 cases/yr of salivary cancers (∼5% of all H&N cancers)
What is the sex predilection and median age at presentation for benign vs. malignant tumors?
Benign: female > male, 40 yo
Malignant: female = male, 55 yo
What is the most common type of benign tumor of the salivary gland, and where is it most commonly found?
Pleomorphic adenoma (65%). It is most commonly found in the parotid glands.
In addition to pleomorphic adenoma, what are some other benign salivary gland tumors?
Warthin tumor (papillary cystadenoma lymphomatosum), Godwin tumor (benign lymphoepithelial lesion, associated with Sjögren), and monomorphic adenoma (oncocytoma, basal cell)
What is the most common malignant salivary gland tumor, and where is it most commonly found?
Mucoepidermoid carcinoma. It most commonly arises in the parotid (most are low grade, but if the tumor is high grade, it needs to be managed with Sg + LND + adj RT).
How are tumors of the salivary gland separated into low vs. intermediate vs. high grade by histology?
Tumors should be assigned a grade by the pathologist. Some tumors are assumed a grade unless specified, though it should always be verified. Acinic cell carcinoma is typically a low-grade tumor. Carcinoma ex-pleomorphic adenoma (CexPA), and salivary ductal carcinomas are almost always high grade. Mucoepidermoid carcinoma must be graded. Adenoid cystic carcinoma (ACC) is often low grade, but rather than grading, pathologists will describe ACC as either tubular, cribriform (low), or solid (high). ACC is often grouped with high-grade tumors as its propensity for poorly defined borders and neurotropism almost always requires multimodal therapy. The nomenclature for salivary gland tumors is also evolving. Thus, mixed malignant tumors are rarely seen as the majority are CexPA, and most adenocarcinomas seen are aggressive salivary duct carcinoma or low-grade polymorphous adenocarcinoma (most commonly seen in the hard palate).
What is the relationship b/t the gland size and malignant nature of the salivary tumor?
Typically, the smaller the gland, the more malignant the tumor.
What is the approximate incidence ratio of benign to malignant tumors in the various salivary glands?
Approximate incidence ratios of benign to malignant tumors:
Parotid, ∼75:25
Submandibular gland, ∼50:50
Sublingual gland, ∼10:90
Minor salivary, ∼20:80
What is the most common malignant histology arising in the submandibular gland?
ACC is the most common malignant histology of the submandibular gland.
What is the most common malignant histology arising in the minor salivary glands?
ACC is the most common malignant histology of the minor salivary glands.
Where are the minor salivary glands found in the H&N?
Minor salivary glands are found in the mucosal lining of the aerodigestive tract. Most are in the OC (85%–90%), with the palate (especially the hard palate) being the #1 site. They can be found in all sites of the OC, nasal cavity, PNS, OPX, and larynx.
What are the risk factors for developing salivary gland tumors?
Ionizing RT, personal Hx of tumor, and family Hx
What is the lymphatic drainage predilection of the parotid, submandibular/sublingual, and minor salivary glands?
Lymphatic drainage predilection:
Parotid: preauricular, periparotid, and intraparotid, with deep intraparotid nodes draining sequentially along the jugular nodes (levels II–IV)
Submandibular/sublingual: levels I–II nodes, less often levels III and IV
Minor salivary: depends on site of involvement and histology
How does the propensity for LN mets relate to the site of origin of the salivary tumor?
The propensity for LN spread is greatest for the minor salivary gland > submandibular/sublingual > parotid gland malignancies.
What is the natural Hx of ACC?
ACC is often low grade (cribriform or tubular), but is very locally infiltrative. PNI with skipped lesions and involvement of large nerves is common, as is DM. Recurrence can be very late, though high-grade tumors (solid type) tend to have a more aggressive course. Nodal mets are uncommon (5%–8%).
