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Pleomorphic adenoma (mixed tumour). The commonest salivary gland neoplasm

Cytological findings: Pleomorphic adenoma

- Cellular aspirates with large amount of myxoid background matrix
- Myoepithelia| cells singly or in sheets
- Epithelial cells in form of tubules or as squamous or oncocytic cells
- Cell nuclei vary in size but have uniform chromatin
- Spindle-shaped mesenchymal cells
- Chondroid or other metaplastic changes sometimes seen

Diferential diagnosis :

- Dominance of one cell type: myoepithelioma
- Cytological atypia: carcinoma ex pleomorphic adenoma
- Globules of basement membrane material: adenoid cystic carcinoma
- Cystic change: retention cyst. Warthin‘s tumour.
- Squamous, mucinous, sebaceous metaplasia: squamous cell carcinoma or mucoepidermoid carcinoma.