Myxoid neoplasms of the adrenal cortex: a rare histologic variant.

The myxoid variant of adrenocortical carcinoma is a rare neoplasm described previously in only two case reports. Because of the rarity of these lesions, the presence of myxoid changes in adrenal cortical neoplasms usually raises the possibility of malignancy. We studied the histopathologic features of 14 cases of myxoid adrenocortical neoplasms, including six adenomas and eight carcinomas. All patients with adenomas with sufficient follow-up (n = 5) were alive with no recurrence of their tumors or evidence of metastatic disease. Four patients with carcinomas died of their disease, two were alive with metastatic disease, and one was alive with no evidence of recurrence or metastatic disease. Histologically, the 14 tumors varied in their myxoid composition, ranging from 10% to 95%. The myxoid foci stained positively with Alcian blue and were usually negative with periodic acid-Schiff and mucicarmine stains. As a group, the immunophenotype of the lesions was typical of other adrenal cortical neoplasms, with positive immunostaining for vimentin, synaptophysin, and alpha-inhibin. One tumor was focally positive for keratin. Myxoid adrenal cortical neoplasms should be included in the differential diagnosis of myxoid retroperitoneal neoplasms. Myxoid changes in adrenal cortical neoplasms may be present in both adenomas and carcinomas, and the usual clinical and histopathologic features for adrenocortical neoplasms should be used to diagnose these neoplasms.