Page 401 - Concise Pathology for Exam Preparation ( PDFDrive )

386
386 SECTION II Diseases of Organ Systems

• SCCs range from well-differentiated keratinizing neoplasms to poorly differentiated,
anaplastic, sometimes sarcomatoid tumours (spindle cell variant of SCC).
• Local metastasis preferentially occurs in the cervical lymph nodes, while distant metas-
tasis is most commonly noted in mediastinal lymph nodes, lungs, liver and bones.

SALIVARY GLANDS
• There are three major salivary glands—parotid, submandibular and sublingual—as well
as innumerable minor salivary glands distributed throughout the mucosa of the oral
cavity. All these glands are subject to inflammation or to development of neoplasms.
• Salivary glands are compound exocrine glands with ductal and acinar portions. The
acinar portion may be serous, mucinous or mixed; and, all acini are lined by luminal
cells, which are enclosed by myoepithelial cells.
• Serous acini have dense, basophilic, Periodic acid–Schiff (PAS)-positive intracytoplasmic
secretory granules containing amylase and a small central lumen.
• Mucous acini are larger than serous acini; have cells with abundant cytoplasm contain-
ing mucin, well-rounded basal nuclei and are arranged around empty lumina; produce
acidic mucins (positive for alcian blue and mucicarmine) and neutral mucins (positive
for PAS).
• Myoepithelial cells surround acini and intercalated ducts, and mediate contraction.
• Ducts are intercalated, striated or interlobular, all with outer basal cells and inner lumi-
nal cells. Intercalated ducts have reserve cells that regenerate acinar tissue and terminal
duct system.

Q. Write briefly on salivary gland tumours.
Ans. Salivary gland tumours (SGTs) are relatively uncommon; they constitute only about
2% of all head and neck neoplasms. Nearly 80% of these tumours occur in the parotid
glands, 15% in the submandibular glands and the remaining 5% in the sublingual and
minor salivary glands. Benign neoplasms make up about 80% of parotid tumours, 50% of
submandibular tumours and less than 40% of sublingual and minor salivary gland
tumours.

Classification
Benign epithelial tumours:
• Pleomorphic adenoma
• Myoepithelioma
• Basal cell adenoma
• Warthin tumour
• Oncocytoma
• Canalicular adenoma
• Sebaceous adenoma
• Lymph adenoma
• Ductal papilloma
• Cystadenoma

Malignant epithelial tumours:
• Acinic cell carcinoma
• Mucoepidermoid carcinoma
• Adenoid cystic carcinoma
• Polymorphous low-grade adenocarcinoma
• Epithelial–myoepithelial carcinoma
• Clear-cell carcinoma; not otherwise specified
• Basal-cell adenocarcinoma
• Malignant sebaceous tumours
• Cystadenocarcinoma
• Low-grade cribriform cystadenocarcinoma

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