Abstract
A case of giant malignant solitary fibrous tumor (SFT) arising in the mediastinum is described. A 51-year-old woman complaining of coughing and dyspnea was operated on for a mediastinal malignant tumor occupying the entire left hemithorax. At operation the tumor was found to originate from the mediastinal subpleural region, extending over the left hemithorax and invading the diphragm. The tumor which was liable to bleed, combined with the invaded lesion, was successfully extirpated. The extirpated tumor was 27×21×17cm in size and 2100g in weight.
Histologically the tumor was composed of spindle cells in a storiform pattern with extensive collagen deposition and partially showed high cellularity and mitotic activity. Immunohistochemistry showed diffuse positive staining of tumor cells for CD34 and vimentin but negative staining for cytokeratin. The definitive diagnosis of giant malignant SFT was made. SFTs occur most commonly in the pleura, but can occur in various organs. SFTs of the mediastinum have been rarely reported in the world with a total of 26 cases so far. This is the third case in Japan.
