Objectives: The oncocytic cell is an epithelial cell with granular eosinophilic cytoplasm extremely rich in mitochondria. It may be observed in different parenchymal tumors of the kidney: oncocytoma, granular cell carcinoma (oncocytic adenocarcinoma), clear cell adenocarcinoma. Renal oncocytoma, a benign tumor, is made up exclusively of regular oncocytic cells.
Methods/results: In granular cell carcinoma (oncocytic adenocarcinoma), different aspects of malignancy are present as necrosis, cellular pleomorphism. In clear cell adenocarcinoma, on the contrary, it is possible to observe only some nests of oncocytic cells.
Conclusions: The Authors underscore the presence of oncocytic cells in such different neoplasms and the possibility, especially in clear cell adenocarcinoma with nests of oncocytes, that needle biopsy or aspiration cytology from such an area can lead to a misdiagnosis.