A case of a borderline adrenal oncocytoma in a 62-year old female

Adrenal oncocytomas are a rare pathology and only about 160 cases have been reported in the literature.

We describe the case of a 62-year old female with an incidentaloma found in the right adrenal gland on a CT scan. Endocrine testing showed a non-secreting lesion. An MRI was performed to get a more precise diagnosis. It excluded a simple adenoma and a malignant tumor had to be suspected. Open adrenalectomy was performed, and pathology results confirmed a borderline adrenal oncocytoma.

Oncocytomas are usually found in the kidneys, salivary glands, parathyroid, lung, pituitary gland, and ovaries. It is important to differentiate them from, for example, pheochromocytomas, adrenal cortical carcinoma, and metastasis. Most oncocytomas are non-functioning (17% are functional). Usually, they are found as incidentalomas on a CT or MRI scan. The only way to confirm the diagnosis at present is pathological examination. Bisceglia and his colleagues have proposed a new system to classify adrenal oncocytomas. The presence of one major criterion indicates malignancy, the presence of one to four minor criteria is indicative of uncertain potential. The absence of all major and minor criteria indicates benign behavior. Treatment options are open surgery, laparoscopic surgery and rarely robotic surgery.

An adrenal oncocytoma remains a rare diagnosis and has a wide array of differential diagnosis. It should be treated by surgical removal and a close follow up is suggested. More research should be done regarding diagnosis, treatment and follow-up.