[Solitary fibrous tumor (SFT) of the thymic area--a case report].

A 52-year-old man was referred to our hospital with a large anterior mediastinal tumor on chest X-ray. A preoperative CT scan revealed the large tumor in front of the ascending aorta. We failed aspiration biopsies for several times because of scant tumor cells. This tumor was totally removed with a small part of the pericardium through median sternotomy after preoperative radiation therapy consisting of a total dose of 25 Gy. There was no metastasis to regional lymph nodes nor dissemination in the anterior mediastinum. The tumor was encapsulated, 9 x 12 cm in size, 270 g in weight with necrotic region induced by preoperative radiation therapy. We made the diagnosis of solitary fibrous tumor of the thymic area by pathological examination and immunohistochemical study. SFT most frequently arises in the pleura and is less frequently observed in the pericardium and peritoneum. But SFT of the mediastinum has been rarely reported in the world and this is the second case in Japan.