Endocrine Abstracts

Introduction: Oncocytic tumor of adrenal gland was defined as a neoplasm composed exclusively or predominantly of oncocytes which are large and polygonal cells with eosinophilic cytoplasm because of abnormal accumulation of mithochondria. Oncocytic neoplasms of the adrenal cortex are extremely rare and are usually non-functioning, benign and incidentally detected.

Case: A 40-year old male patient, for whom a large mass in the adrenal gland was diagnosed incidentally on abdominal ultrasonography and MRI. The physical examination and laboratory tests were within normal limits. On the dynamic abdominal MRI imaging 9.5×9.5×10.5 cm mass lesion was observed in the right surrenal region. 24-hour urine dopamine and VMA levels were slightly higher [VMA: 8.4 mg/24 h (0–6.6 mg/24 h) and Dopamine: 435.1 μg/24 h (<400 μg/24 h)]. Right -side adrenalectomy was applied to the patient. The histopathological diagnosis was reported by the Pathology Department as oncocytic adrenocortical tumor with uncertain malignant potential according to the Lin-Weiss-Bisceglia system (Large size and capsule invasion were detected). Immunohistochemistry (IHC) of the tumor cells were found positive for synaptophysin and negative for inhibin and chromogranin.

Conclusion: Adrenocortical oncocytoma is a very rare abnormality observed within the adrenal cortex. It is usually benign, non-functioning, large and diagnosed incidentally. Adrenal gland masses are best visualized on CT or MRI but still no definitive features can differentiate benign from malignant adrenal oncocytic neoplasm on imaging. Diagnosis is made histopathologically, so adrenalectomy is the mainstay of therapy and laparoscopy is now the most diffuse approach. According to Weiss criteria: the presence of one major criteria (high mitotic activity, atypical mitoses or venous invasion) indicating malignancy, one to four minor criteria (Large size, necrosis, capsular or sinusoidal invasion) indicating uncertain malignant potential (borderline) and the absence of criteria indicates a benign tumor. Our case was interesting because malignancy was clinically suspected before the operation, but the mass was found to be an oncocytic adrenocortical tumor with uncertain malignant potential through postoperative histologic assessment. Therefore, an oncocytic adrenocortical tumor with uncertain malignant potential as in this case is considered to require long-term follow-up through clinical, hormonal, and imaging evaluation owing to its malignant potential.