Adrenal oncocytic neoplasm: a systematic review.

INTRODUCTION Oncocytic neoplasms as tumors arising in the adrenal glands are rare, usually considered as nonfunctional and benign. In the current literature, there are extremely limited reports of adrenal oncocytic neoplasms; as to date, only 147 cases have been described. The rarity of the event prompted this study which reviews and presents the incidence, histology, diagnosis and therapy of adrenal oncocytic neoplasms. MATERIALS AND METHODS A review by systematic literature search was done using the MEDLINE®/Cochrane libraries from 1950 to date using the medical subject headings 'oncocytoma', 'adrenal gland', 'adrenal oncocytoma', 'adrenal oncocytic neoplasm' and 'adrenal oncocytic carcinoma'. RESULTS Adrenal oncocytic neoplasm is a rare disease, usually incidentally detected because only 17% are functional adrenal masses. The typical oncocyte displays abundant granular eosinophilic cytoplasm, due to the accumulation of mitochondria. Computed tomography and magnetic resonance imaging are not able to identify or differentiate benign and malignant oncocytic neoplasms. The mainstay of therapy is adrenalectomy, recently performed by laparoscopy. The prognosis is good for benign tumors, while adrenocortical oncocytic carcinoma has a poor survival rate of only 5 years. CONCLUSIONS Adrenal oncocytic neoplasm, a rare and mostly benign tumor, usually presents as an incidental, large adrenal mass; surgery is the mainstay of therapy, by means of laparoscopy which is now the most diffuse approach to adrenalectomy.