Oncocytic adrenocortical neoplasm with undetermined malignant potential and autonomous cortisol secretion.

Increasing incidence of adrenal incidentalomas with hypercortisolemia not associated with overt features of Cushing's syndrome has led to the evolution of the term autonomous cortisol secretion. Oncocytic adrenocortical neoplasms (OANs) are rare adrenal cortex neoplasms with only 250 reported cases worldwide. We present a woman in her 30s with menometrorrhagia, weight gain and increasing abdominal girth who was found to have a large right adrenal mass on abdominal CT scan. Serum cortisol was not suppressed after 1 mg dexamethasone (31.5 µg/dL) and adrenocorticotrophic hormone was not detectable (<1.0 pg/mL). She underwent right adrenalectomy under glucocorticoid coverage. Hypertension, weight, visceral adiposity and menometrorrhagia improved postoperatively. Histopathology with immunohistochemistry showed OAN with undetermined malignant potential. These kinds of tumours can only be definitively diagnosed postsurgically using the Lin-Weiss-Bisceglia system. Although they have better prognosis compared with adrenocortical carcinomas and do not require chemotherapy, patients should be closely monitored to identify recurrence promptly.