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| S. no. | Lesion | Microscopic appearance |
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| (1) | Oncocytic mucoepidermoid carcinoma | Predominance of oncocytes showing granular eosinophilic cytoplasm along with large cystic structures lined by mucous cells, epidermoid cells, and intermediate cells |
| — | Lesion | Microscopic appearance | Differentiating feature from OMEC |
| (2) | Oncocytosis | Unencapsulated foci of oncocytic cells appearing in multiple separate nodules. The lesion contains residual (nononcocytic) salivary gland parenchyma | Absence of epidermoid, mucous, and intermediate cells either focally or predominantly |
| (3) | Oncocytoma | Encapsulated tumour exhibiting an organoid/alveolar growth pattern separated by thin fibrous connective tissue septa | Encapsulation. Absence of mucous, epidermoid, and intermediate cells |
| (4) | Oncocytic carcinoma | Unencapsulated, single, or multinodular tumour. Oncocytic cells exhibit pleomorphism. Infiltration into the salivary gland parenchyma in the form of trabeculae, sheets, and nests | Absence of mucous, epidermoid, and intermediate cells and presence of atypical features |
| (5) | Pleomorphic adenoma | Encapsulated, presence of chondromyxoid areas, characteristic melting pattern seen | Encapsulation. Chondromyxoid areas, presence of ducts |
| (6) | Warthin’s tumour | Papillary cystic lesion with bilayered oncocytic epithelium overlying lymphoid stroma | Absence of mucous cells, not infiltrative |
| (7) | Acinic cell carcinoma | Forms a solitary mass or multiple nodules and invades in broad fronts. Predominantly cellular with less fibrous stroma. Tumour cells arranged in organoid sheets which are traversed by ramifying blood vessels. Prominent growth pattern: microcyst pattern | Absence of/minimal fibrous stroma. Absence of mucous cells, epidermoid, and intermediate cells |
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