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.

Oncocytoma (Wikipedia)

An oncocytoma is a tumor made up of oncocytes, epithelial cells characterised by an excessive amount of mitochondria, resulting in an abundant acidophilic, granular cytoplasm. The cells and the tumor that they compose are often benign but sometimes may be premalignant or malignant.

Oncocytoma
Specialty	Oncology
Symptoms	4