Oncocytic Adreno Cortical Tumors: Pathological Features of 16 Cases and Review of the Literature.

Oncocytic neoplasms of the adrenal gland are extremely rare tumors. These tumors differ from their nononcocytic counterparts in some respects. The aim of this study was to review and discuss the clinical, histological, and immunohistochemical features of as well as the prognosis for these rare tumors. In total, 16 cases diagnosed as adrenocortical oncocytic neoplasms between January 2011 and December 2016 were included in the study. The demographic data, gross characteristics, histological data, and immunohistochemical data (Chromogranin-A, Synaptophysin, α-Inhibin, Melan-A, Ki67, PHH3) were reevaluated. The follow-up data for these patients were added in January 2017. Of the 16 cases, 12 were adrenocortical adenoma, 1 was borderline adrenocortical tumor, and 3 were adrenocortical carcinoma. The tumors equally affected both genders. The tumors were not generally large. Tumor cells had pleomorphic nuclei in ten cases, but it was more obvious in one case. The mitotic figure count was low in most tumors. Atypical mitosis and necrosis were observed in three and four tumors, respectively. None of cases included sinusoidal invasion, vascular invasion, or capsular invasion. We detected the expression of at least one specific marker (e.g., Melan-A, Inhibin-α) of the adrenal cortex in all tumors. None of the tumors were immunoreactive for Chromogranin-A. Ki-67 proliferation index was lower than 5% in all cases except three oncocytic carcinomas. In two cases, PHH3 positivity was not seen, while it was lower than 3 of 10 high-powered fields in ten cases and higher in 4 cases. All patients were alive and disease free except for two patients with adrenocortical carcinoma. In conclusion, determining the clinical, histological, and immunohistochemical characteristics of these extremely rare tumors can provide important information for early diagnosis, treatment, and follow-up of these cases.