Adrenal oncocytic neoplasm with uncertain malignant potential.

Adrenal oncocytic neoplasms (AONs) are a rare group of tumours with a somewhat uncertain natural history and clinical behaviour. Out of 46 cases of AON reported to date, 6 cases were histologically classified as neoplasms with uncertain malignant potential. We report the case of a 35-year-old male with an incidentally-detected large AON with mostly benign morphology and some characteristics which would make its behaviour uncertain.