[Myxoid type of malignant fibrous histiocytoma in the anterior mediastinum; report of a case].

A 58-year-old man was admitted to our hospital complaining of right chest pain. Chest X-ray and chest computed tomography (CT) disclosed a 9 cm mass in the right anterior mediastinum. The tumor demonstrated low signal intensity on T1-weighted images, and high signal intensity on T2-weighted images. It showed delayed enhancement on dynamic magnetic resonance (MR). The operation was performed and the tumor including the infiltrated pericardium and upper and middle lobe of right lung was resected. Histologically, the tumor showed a multinodular proliferation of spindle-shaped or polygonal tumor cells with abundant myxoid background. The histopathological diagnosis of the tumor was myxoid malignant fibrous histiocytoma (MFH). This is a case report of primary myxoid MFH in the anterior mediastinum. The case is rare in its primary site, but it is typical in CT and MR findings.