Adenomatoid tumor of the mediastinum.

Adenomatoid tumors are relatively uncommon benign tumors of mesothelial origin, usually occurring in the male or female genital tracts. Extragenital adenomatoid tumors are quite rare. Here, we report a very rare case of adenomatoid tumor of the mediastinum. A 67-year-old woman was admitted to our hospital with an abnormal shadow that appeared on a routine chest radiograph. After further radiological evaluation suggested a diagnosis of thymoma, surgical resection was performed, and histologic and immunohistochemical examination yielded a definitive diagnosis of adenomatoid tumor. The patient remained clinically free of disease at follow-up, 19 months later.