Oncocytic adrenocortical neoplasm: a rare tumour of uncertain malignant potential: a case report

Abstract

<h3>Aims</h3> Oncocytic adrenocortical neoplasms are uncommon. To date, less than 50 cases have been described in the English literature. They are mostly benign tumours but a couple of malignant cases have been reported. In this study, we reported an oncocytic adrenocortical neoplasm with some unusual features. <h3>Methods</h3> A non-functional adrenal tumour was detected in a 39-year-old woman incidentally on ultrasound for gynaecological symptoms. She underwent left adrenalectomy which showed a large mass weighing 1384g and measuring 180 × 140 × 115mm. Histopathological examination of the mass was performed. <h3>Results</h3> The tumour was composed of tumour cells with prominent oncocytic cytoplasm. Electron microscopy showed numerous mitochondria which confirmed the oncocytic nature of this tumour. The tumour cells showed weak staining for inhibin and a low Ki-67 (<5%). It fulfils one of the minor modified Weiss criteria for malignancy (i.e., large size and weight) but lacks other features of malignancy. Thus, it was diagnosed as oncocytic adrenocortical neoplasm of uncertain malignant potential. <h3>Conclusion</h3> We reported an unusual oncocytic adrenal neoplasm of uncertain malignant potential. To our knowledge, this entity is rare and follow-up is necessary to determine the biological behaviour.