Oncocytic Metaplasia Essay

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The normal striated duct cells of the salivary glands contain many mitochondria and have prominently eosinophilic cytoplasm, which suggests that oncocytomas develop from striated duct cells. But oncocytic metaplasia involves other cells besides striated duct cells, including acinar cells. Therefore, any of the several cellular elements of the salivary gland could be the origin of oncocytoma. An estimated 60% of the cytoplasmic volume of salivary oncocytes is occupied by mitochondria. [6]
The proliferation of oncocytes in salivary glands varies from small isolated foci, to diffusely scattered small foci, to clinically evident nodules. Small proliferations, especially when multiple, are generally considered hyperplastic while large, dominant,
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Paradoxically, clear cells dominate some lesions, particularly in multinodular oncocyitc hyperplasia. The clear cell cytoplasm is due to the marked accumulation of cytoplasmic glycogen and margination of the mitochondria in the oncocytes. The glycogen can be demonstrated by staining with PAS before and after tissue digestion with diastase. Conventional eosinophilic oncocytes are frequently evident among the clear cells and help confirm the diagnosis. Clear cell oncocytomas have the same architectural arrangement as conventional…show more content…
These include phosphotungstic acid-hematoxylin (PTAH), Novelli, Cresylecht violet V, and Kluver-Barrera Luxol fast blue.[6]
The cytological features are similar to those of Warthin’s tumour except for the absence of lymphocytic cells.[6]
Immunohistochemical findings
Oncocytomas are typically reactive with immunostains for cytokeratins and are strongly reactive with antimitochondrial antibody. [6]
For the most part identification of oncocytoma is uncomplicated. Warthin’s tumour is prominent in the DD. Rarely, oncocytic metaplasia in other salivary gland neoplasms is extensive and leads to confusion with oncocytoma. Pleomorphic adenoma and mucoepidermoid carcinoma are the salivary gland neoplasms that most frequently demonstrate oncocytic metaplasia. Other clear cell neoplasms need to be distinguished from the uncommon clear cell
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