Myxoid adrenocortical adenoma with a pseudoglandular pattern: a case report and literature review

Adrenocortical adenoma is a benign neoplasm derived from cells of the adrenal cortex. The myxoid variant of this tumor is extremely rare. To our knowledge, only 23 cases of myxoid adrenocortical adenoma have been reported so far and 19 of them mentioned the pseudoglandular pattern. We reported a new case of 56-year-old Chinese female patient whose left adrenal gland was shown a neoplastic lesion by computed tomography (CT) and magnetic resonance (MR) imaging. Histopathological study showed that the mass was a myxoid adrenocortical adenoma with a pseudoglandular pattern. Then, we performed immunohistochemistry with 28 biomarkers to make differential diagnosis and found that tumor cells were diffusely positive for vimentin, melan-A, CD56, NSE and USP10, and focally positive for cytokeratin pan, cytokeratin 8/18 and VEGF. The labeling index of Ki-67 and Cyclin D1 were about 1% and 50%, respectively. No immunoreactivity was found for EMA, cytokeratin 7, HMB45, S-100, alpha-inhibin, calretinin, synaptophysin, chromogranin A, P53, EGFR, MMP2, DNA topo II alpha, CA125, E-cadherin, P63, P16 and Her-2. The patient has been followed up for 37 months after tumor resection and no evidence was found to suggest any local recurrence or any metastatic disease. Myxoid adrenocortical adenoma with a pseudoglandular pattern is extremely rare. The accurate diagnosis should be based on combined consideration of clinical characteristics, CT, MR imaging and pathological features, and should be distinguished from other retroperitoneal myxoid tumors.