[Clinicopathologic features of myxoid adrenocortical adenomas]

Objective: To study the clinicopathologic characteristics, immunophenotype, pathologic diagnosis and differential diagnosis of myxoid adrenocortical adenomas. Methods: The clinical data, histological features and immunohistochemical results of 4 cases of myxoid adrenocortical adenomas were analyzed, which were collected from January 2014 to December 2016 at Guangdong General Hospital, with review of literature. Results: Four cases of myxoid adrenocortical adenomas were presented. The patients ages ranged from 26 to 45 years (mean =35 years). Microscopically, it showed a typical morphology, characterized by small-sized tumor cell cords or pseudo-glands embedded in an abundant extracellular myxoid matrix. Immunohistochemical staining showed tumor cells were strongly positive for Melan A, vimentin and focally for α-inhibin, one case showed strong and diffuse positivity for CAM5.2, and two cases showed diffuse positivity for synaptophysin, while negative for CgA, S-100 protein, epithelial antigen, CK7, CK20 and CKpan. Conclusions: Myxoid adrenocortical adenomas are extremely rare, which may cause confusion with metastatic well-differentiated neuroendocrine tumours, sex cord-stromal tumoursor metanephric adenoma. Recognition of this entity would be beneficial for pathologists to avoid misdiagnosis, and unnecessary treatment.