Endocrine Abstracts

Introduction: Hormonally active adrenocortical oncocytoma is a very rare neoplasm. Adrenal oncocytomas are mostly considered as non-functioning, benign tumors, with the size of generally >6 cm and lack of pathognomonic features on radiological examinations.

Case Report: A 41-year-old woman was referred to the endocrinologist in April 2021 due to weight gain, resistant arterial hypertension and menstrual irregularities for the last several years. She has been infertile for 10 years, though 5 years ago she delivered a preterm baby girl by the 35th week of pregnancy. Physical examination revealed cushingoid characteristic features: dorsal cervical fat pad, moon facies, fragile skin and thin extremities. Cushing syndrome was confirmed by an overnight 1 mg dexamethasone suppression test, an elevated free cortisol on a 24-hour urine collection, suppressed ACTH level and low DHEA-S level. Primary hyperaldosteronism was excluded by an oral salt loading test. Urinary metanephrines were normal. HBA1C-6.0%. Abdominal CT and MRI revealed left sided adrenal heterogeneous lesion (adenoma) measuring 2.3X2.8X2.2 cm with a calcification focus in the periphery. She was also revealed small liver hemangiomas and NAFL disease. In July 2021 the patient underwent laparoscopic left adrenalectomy. To prevent postoperative adrenal insufficiency, the patient was medicated with hydrocortisone. The operative adrenal gland measured 6x2.5x2.5 cm, with a nodule of 2.5x2.2x2.0 cm of well-defined limits, yellowish. The histological and immunohistochemical analysis revealed the diagnosis of adrenocortical neoplasm with predominance of oncocytic cells in solid-trabecular structures (adrenocortical oncocytoma), having uncertain malignant potential. The doses of hydrocortisone were tapered slowly and stopped 3 months later. 6 months after surgery her cortisol, DHEA-S and electrolyte levels were normal, without any radiologic evidence of recurrence. She is currently in follow up.

Discussion: Adrenocortical oncocytomas are extremely rare tumors with almost 200 published cases, first reported in 1986 by Kakimoto. Although it is by definition, non-functioning, recent data indicate that 17.0-31.5% of adrenal oncocytomas have hormonal activity. By origin oncocytomas are epithelial tumours composed of large eosinophilic cells, due to mitochondria-rich cytoplasm. The frequency of non-functioning oncocytomas is higher in female. The diagnosis of these neoplasms is mostly based on histological and immunohistochemical analysis. The Lin-Weiss-Bisceglia risk system is used to distinguish malignant oncocytic tumors, with major and minor criteria for differentiation. Small oncocytomas are commonly benign tumors, but in our clinical case the hormonally active oncocytoma, with two minor criteria (necrosis and capsular invasion), was classified as having uncertain malignant potential, thus suggesting important prognosis and need for close follow-up.