General Information about Oncocytoma - An oncocytoma is an epithelial tumor composed of oncocytes, large eosinophilic cells with small, round, benign-appearing nuclei and large nucleoli. - Oncocytoma can arise in various organs. - Renal oncocytoma is thought to originate from the intercalated cells of collecting ducts in the kidney. - Salivary gland oncocytoma is a well-circumscribed, benign neoplastic growth also known as oxyphilic adenoma. - Thyroid oncocytomas can be benign (adenomas) or malignant (carcinomas), also known as Hürtle cell tumors. - Grossly, oncocytic adenomas are encapsulated, solid nodules with a characteristic brown cut surface. - Minimally invasive oncocytic carcinomas appear indistinguishable from adenomas, while widely invasive oncocytic carcinomas display obvious macroscopic invasion and vascular involvement. - Cytologic features alone cannot reliably distinguish oncocytic adenomas from carcinomas. - The identification of transcapsular or vascular invasion is the only criterion for diagnosing malignancy.

Renal Oncocytoma - Renal oncocytoma represents 5% to 15% of surgically resected renal neoplasms.

Salivary Gland Oncocytoma - Salivary gland oncocytoma comprises about 1% of all salivary gland tumors. - Histopathology of salivary gland oncocytoma is characterised by sheets of large swollen polyhedral epithelial oncocytes. - These oncocytes are granular acidophilic parotid cells with centrally located nuclei. - The granules are created by the mitochondria. - Salivary gland oncocytomas are most common in individuals aged 70-80, particularly females. - They primarily occur in the parotid gland (85-90% of cases). - These masses are firm, slowly growing, and painless, typically measuring less than 4cm. - Bilateral occurrence may also be observed in some cases.

Thyroid Oncocytoma - Patients with thyroid oncocytomas typically present with a thyroid nodule, often with normal thyroid function. - Larger or invasive tumors may cause difficulty swallowing or talking.

Additional Information - Micrograph of a renal oncocytoma stained with H&E. - Gross appearance of a nephrectomy specimen containing a renal oncocytoma, showing rounded contour, mahogany color, and a central scar. - Kidney, renal cell carcinoma, and Hurthle cell are related terms. - Citations are needed to support the statements in each group.