Acinic cell carcinoma

Acinic cell carcinoma

· Account for about 1% of salivary gland tumors

· Show an almost uniform pattern of large cells similar to serous cells,with granular basophillic cytoplasm,often in an acinar arrangement

· Characteristic feature-scattered round 'holes' throughout the entrapted secretion

· Sometimes these are so numerous as to give the tumor a lce like appearance

· Despite,apperantly benign histolological appearances,acinic cell carcinomas can be invasive and metastasise

· More obviously malignant varients with nuclear pleomorphism and hyperchromatism and also occationally seen microscopically.

Polymorphus lowgrade adenocarcinoma

Polymorphus low grade adenocarcinoma

· Arises in minor glands

· particularly in the palate

· Cytologically benign-looking pale staining cells in lobular,papillary or papillary cystic,cribriform or trabecular configurations

· It is invasive and can spread along nerve sheaths but rarely metastatise

Adenoid cystic carcinoma

Adenoid cystic carcinoma

· Rounded groups of small darkly stained of alomst uniform size,surrounding multiple small clear spaces(cribriform or swiss cheese pattern)

· Grow relatively slow

· Tend to infiltrate along the nerve sheths

· When they reach and spread along bony canals their extent is considerably greter than radiographs show

Mucoepidermoid carcinoma

Muco-epidermoid carcinoma

· Account for 3-9% of salivary gland tumors

· Consist of two cell types,namely large,pale mucus secreting cells surrounded by epidermoid(squamous)cells

· If mucoid the tumor tends to be cystic

· If mainly epidermoid,the tumor issolidand often then more aggressive

· no well defined capsule,tumor usually grows slowly

· Benign cytological appearances,mucoepidrmoid carcinomas can be invasive and occasionally metastasise

Warthin's tumour

Warthin's Tumour

· Arises in the parotid gland

· Tall,eosinophilic columnar cells which form a much folded layer covering dense lymphoid tissue,includng many germinal centres

· These structures line and form papillary projections into cystic spaces

Pleomorphic adenoma

Pleomorphic adenoma

· Account for about 75% of parotid tumors

· Arise mainly from duct epithelum or myoepithelial cells

Important histological features

· Capsule never complete

· Ducts

· Sheets or stands of dark staining epithelial cells

· Squamous metaplasia and focci of keratin

· Fibrous and elastic tissue

· Myxoid tissue

· Cartilage,sometimes calcified,rarelytrue bone formation.

· The fibroid,myxoid,or cartilagenous,mesenchymal elements are due to the pluripotential properties of myoepithilial cells.