The unique case of adrenocortical malignant and functioning oncocytic tumour

Adrenocortical oncocytoma is extremely rarely found. Only a little more than thirty cases of adrenal oncocytoma, mainly nonfunctioning and benign, have been reported in the literature. Adrenal mass 150×160×172 mm in size and enlarged periarterial lymph nodes were found in CT examination performed in 51-year-old male. Main complaints: weight loss, general asthenia and abdominal pain. Physical examination: elevated blood pressure (180/120 mmHg), no features typical of Cushing's syndrome. Abnormal laboratory findings: oral glucose tolerance test revealed diabetes, elevated serum dehydroepiandrosterone-sulfate (1101.9 μg/dl; normal, 59-452), elevated serum cortisol following overnight 1 mg dexamethasone test (5.1 μg/dl; normal, <1.8), increased urinary excretion of 17- hydroxycorticosteroids (18.1 mg/24 h; normal, 2.0-7.0) with pathological response to high-dose dexamethason test (16.6 mg/24). On laparotomy, the lesion was considered unresectable because of evident - confirmed by intraoperative ultrasound - tumour infiltration of the inferior caval vein. The large biopsy specimen was obtained for histological examination in which tumour fulfilled criteria proposed by Bisceglia et al. for adrenocortical oncocytic borderline tumour. On immunohistochemistry, the lesion showed cytoplasmic reaction for cytokeratin, vimentin and synaptophysin. The presented case appears to be the first malignant and functioning adrenocortical oncocytic tumour reported and confirms the complexity of its biology.