SUN-179 Oncocytic Adrenocortical Carcinoma: A Case Report

Adrenocortical carcinoma (ACC) is a rare tumor with a poor prognosis. Oncocytic variant of adrenocortical carcinoma is considered to be an even more rare malignancy with four reported in the literature in 2002 and thirty-six documented in 2015 (i ii). This case report illustrates the case of oncocytic ACC. A 40-year-old woman post-hysterectomy from cervical cancer presented to the ER with severe left flank and back pain for two weeks. There was no weight loss or early satiety. CT scan revealed a large left adrenal mass measuring 12x9x13 cm, displacing the left kidney inferiorly with no metastasis to nearby structures. We ruled out functional adrenal mass through a 24-hour urine collection and blood work, then performed open left adrenalectomy. Grossly, it was a large, tan-colored mass, weighing approximately 2,500 grams. On biopsy, we incidentally found the mass to be oncocytic adrenocortical carcinoma. Using the Lin-Weiss-Bisceglia criteria, it met two major and one minor criteria, when only one major criterion is required to indicate malignancy. Immunohistochemical stains showed that the tumor cells were positive for Mart-1, inhibin, and synaptophysin. Quantitative Ki-67 showed a proliferation index of 10% in average (>5% is considered malignant). Even though adrenocortical carcinoma, specifically the oncocytic variant of ACC, is a very rare occurrence, it should be on the differential diagnosis for a chief complaint of unilateral flank pain with a large adrenal mass on CT due to its poor prognosis. Endnotes (i) Hoang, M., Ayala, A. & Albores-Saavedra, J. Oncocytic Adrenocortical Carcinoma: A Morphologic, Immunohistochemical and Ultrastructural Study of Four Cases. Mod Pathol 15, 973-978 (2002) doi:10.1038/modpathol.3880638 (ii) Kalra S, Manikandan R, Srinivas BH. Oncocytic adrenocortical carcinoma--a rare pathological variant. BMJ Case Rep. 2015;2015:bcr2014208818. Published 2015 Apr 24. doi:10.1136/bcr-2014-208818