Chapter 25 - Salivary Gland Flashcards
What is the most common tumor of salivary gland?
For what non-neoplastic indications are biopsies done?
Pleomoprhic adenoma
Sjogren’s syndrome, inflammatory lesions (chronic sialadenitis or lymphoepithelial cyst)
What are the three major salivary glands?
What generalizations can be made about salivary glands?
Parotid, sublingual, submandibular
The smaller the gland, the more likely its neoplasm is malignant. Also, the more mucinous and less serous.
What are the normal three cellular components of salivary glands?
Secretory cells: Serous (wedge-shaped with purple granules) and mucinous (like goblet cells)
Duct cells: Terminal/intercalated, striated, and interlobular
Myoepithelial cells: Pale stellate with small nuclei (hard to find!)
Distinguish the three types of duct cells in salivary gland.
Intercalated ducts: Small profiles with low cuboidal epithelium.
Striated duct: Proximal, larger pink columnar cells.
Interlobular/excretory ducts: Pseudostratified columnar epithelium +/- goblet cells.
What are the four morphologies of myoepithelial cells?
Spindled
Plasmacytoid
Epithelioid
Clear
What is the best method to triage if a salivary neoplasm is malignant?
Evaluate the periphery or capsule for invasion. Benign lesions are encapsulated, whereas malignant tumors are infiltrative.
Recite and relate the cells of origin for the most common benign salivary gland adenomas.
Pleomorphic adenoma / myoepithelioma
Epithelial-myoepithelial
Basal cell adenoma
Epithelial-myoepithelial
Warthin’s tumor, oncocytoma
Striated duct cells
Recite and relate the cells of origin for the most common low-grade salivary malignancies
_Mucoepidermoid carcinoma (low-grade)_ Interlobular duct cells
Polymorphous low-grade adenocarcinoma
Epithelial-myoepithelial
Acinic cell carcinoma
Serous acinar cells
Recite and relate the cells of origin for the most common high-grade salivary malignancies
_Mucoepidermoid carcinoma (high-grade)_ Interlobular duct cells
Adenoid cystic carcinoma
Epithelial-myoepithelial
What is a pleomorphic adenoma?
Where do they most often occur?
A biphasic tumor with epithelial and myoepithelial components.
Most common in the parotid.
Describe the morphologic appearance of pleomorphic adenoma.
A circumscribed, usually encapsulated tumor with a mesenchymal-like component (usually myxoid, but can be chondroid or osseous). The epithelial component may be ductular or myoepithelial.
What is the diagnosis for a pleomorphic adenoma which seems to have a carcinoma component?
Carcinoma ex-pleomorphic adenoma
What is a myoepithelioma? How can it be distinguished?
What about a basal cell adenoma?
A pleomorphic adenoma with very little mesenchymal component and no ductular differentiation. Myoepithelium is positive for S100, cytokeratin, GFAP, and actin.
Basal cell adenoma has no mesenchymal component either, but has a population of basaloid cells.
Describe the morphologic appearance of a Warthin’s tumor.
How can it be distinguished from a lymphoepithelial cyst?
Papillary and cystic lesion lined by a double layer of oncocytic cells atop a prominent lymphoid infiltrate. Can be bilateral!
Lymphoepithelial cysts have a thin ragged epithelial lining instead of an oncocytic one.
What factors contribute to the grading of a mucoepidermoid carcinoma?
Percentage of cystic component
Tumor necrosis
Anaplasia
Mitoses
Neural invasion
Describe the morphologic appearance of a mucoepidermoid carcinoma.
A mixture of squamous, epithelioid, and clear cells of which any can dominate. Note intracellular mucin, usually with PAS or mucicarcmine stain. Infiltrative. Resembles an inflamed or metastatic duct.
Describe the morphologic appearance of adenoid cystic carcinoma.
Very blue, cellular, with dense nuclei with high N:C ratio. Solid or tubular with profound cribriforming and luminal balls of hyaline material.
Why is adenoid cystic carcinoma so aggressive?
What if a squamous area predominates?
What other lesions should be considered?
It is very invasive and loves nerves.
Favor basaloid squamous cell carcinoma instead.
Cylindroma (skin), polymorphous low-grade adenocarcinoma (lip/palate), basal cell adenoma (well-circumscribed)
Describe the morphologic appearance of acinic cell carcinoma.
Resembles normal parotid, minus ducts. Pushing rather than infiltrative border. Can have nonserous cell types present. Follows four architectural patterns.
What are the four architectural patterns of acinic cell carcinoma?
Solid
Microcystic (iregular holes, unlike adenoid cystic)
Papillary cystic
Follicular (like thyroid)
What is a PLGA and where does it occur?
(polymorphous low-grade adenocarcinoma)
Resembles a pleomorphic adenoma with bland epithelium, but is infiltrative like lobular carcinoma. They occur almost exclusively in the intraoral minor salivary glands.
Normal salivary gland
Arrow: Salivary duct
Arrowhead: Columnar mucinous cells
Pleomorphic adenoma
Small and cytologically benign epithelial cells with a myxoid stroma
Left: Parotid gland with mostly serous glands draining into intercalated ducts (arrowhead). Striated ducts are larger and more oncocytic (arrow)
Right: Interlobular ducts (arrow) with pseudostratified epithelium
Warthin’s tumor
Note cyst with double-layer of oncocytic cells and dense lymphoid infiltrate
Low grade mucoepidermoid carcinoma
Clear goblet-like mucinous cells (arrow) and squamous cells (arrowhead).
Adenoid cystic carcinoma
Note small nuclei but high N:C ratio and classic cribriforming.
Acinic cell carcinoma, solid pattern
Arrow: Tumor cells with serous acinar morphology
Acinic cell carcinoma, microcystic pattern
Note irregular spaces. No serous blue granules
Polymorphous low-grade adenocarcinoma
Arrow: Small tubules of bland cells
Arrowhead: Intervening benign mucinous glands
