[Malignant mediastinal schwannoma associated with von Recklinghausen's disease--a resected case].

A case of malignant mediastinal schwannoma associated with von Recklinghausen's disease is reported. A 44-year-old woman was admitted to Chiba University Hospital because of an abnormal shadow on chest X-ray film. CT scan showed a cystic tumor in upper mediastinum and then tumor extirpation was performed. This cystic tumor was related to the sympathetic trunk and 60 x 35 x 33 mm in diameter. Its cut surface showed a thick irregular capsule and multilocular. Microscopic examination disclosed malignant cells with mitosis associated with neurofibroma. An immunohistochemical staining of these malignant cells with anti S-100 protein showed positive reaction. From these findings this tumor was diagnosed as malignant schwannoma. There is no evidence of recurrence two year after the operation. This is the first case of malignant schwannoma with cystic formation in Japan.