Retroperitoneal cystic teratoma masquerading as an incidentally discovered adrenal mass

To report a case of a retroperitoneal cystic teratoma that obscured and compressed the adrenal gland, mimicking a primary adrenal tumor.

The presenting manifestations, radiographic characteristics, gross and microscopic pathologic features, and results of surgical therapy and long-term follow-up are described.

A 50-year-old African American woman with a 2-year history of low back pain and night sweats had a computed tomographic scan of the abdomen, which revealed an incidental 8 by 4 by 3.5-cm left adrenal mass without a clear plane between the mass and the left crus of the diaphragm. Laboratory studies excluded a functioning adrenal tumor. The tumor was resected laparoscopically. It was compressing but not involving the adrenal gland, nor was it involving the diaphragm. Microscopic evaluation revealed a benign mature cystic teratoma characterized by cystic spaces lined by respiratory epithelium with cartilage, bone, lymphoid tissue, smooth muscle, and ganglionic tissue in the cyst wall. The patient had an uneventful postoperative course and is free of recurrence after 18 months of follow-up.

Although rare, a mature cystic teratoma of the retroperitoneum that compresses the normal adrenal gland may masquerade as a primary adrenal tumor and should be included in the differential diagnosis of a nonfunctioning adrenal incidentaloma.