Clinical and pathological analysis of 116 cases of adult adrenal cortical adenoma and literature review

BACKGROUND The aim of this study is to investigate origin, gross features, microscopic features, immunohistochemical properties, and differential diagnosis of adrenal cortical adenoma (ACA) in patients ≥20 years old. METHODS The clinicopathological features of 116 cases of ACA and the immunohistochemical features of 50 cases of ACA were evaluated, and the relevant literature was reviewed. RESULTS In our cohort, 76.72% (89/116) of the cases were functional, and 27 cases had non-functional, benign adrenal adenomas. ACA presented as an island tumor with an envelope, and the mean tumor size was 3.6 cm (range 1-5 cm), with a mean tumor weight of 9.28 g (range 5-113 g). The shape of the tumor cells was consistent, and mitosis was rarely observed. Forty of the 46 patients with cortisol-secreting ACA had tumors containing granule cells. Primary aldosteronism was observed in 43 cases. Thirty-eight cases had endoscopically visible tumors, with clear cells and lipid-rich cytoplasm arranged in irregular patches or strips. Cortisol-producing ACAs were associated with atrophy of the non-tumorous cortex. Adrenocortical adenomas displayed positive immunohistochemical staining for MELAN-A, Syn (46 of 50 cases of ACA), NSE (44 of 50 cases of ACA), Vim (42 of 50 cases of ACA) and Ki-67 <5% (24 of 50 cases of ACA; the remaining 26 cases were negative for Ki-67). CONCLUSION Prediction of endocrine syndrome in functional ACA was possible based on its structure and morphologic features, which could prevent an unanticipated postoperative crisis. However, a clinical study is needed to validate these findings.