Aggressive Malignant Solitary Fibrous Tumor of Anterior Mediastinum: A case report

초록

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor originating at any site in the soft tissue. Most of them are benign but up to 15% behave aggressively. Features suggesting malignancy are hypercellularity, at least focal pleomorphism, >4 mitoses/10HPF, necrosis and infiltrative margin. Usual SFT shows characteristic diffuse immunoreactivity for CD34. Malignant form, however, can be CD34 negative. We present a case of aggressive malignant SFT of anterior mediastinum. A 60-year-old-man was admitted due to a 12×12 cm anterior mediastinal mass with several additional masses along the pleura and diaphragm on chest CT. The result of needle biopsy was malignant spindle cell neoplasm with myofibroblastic differentiation. In spite of chemotherapy, the anterior mediastinal mass increased in size and extended steadily. Moreover, several nodules newly appeared on right lung, pericardium, aorta and paraesophagus. A palliative debulking surgery was performed. Grossly, several huge masses with gray tan, fish flesh-like cut surface were submitted. On microscopic examination, tumor showed alternating cellularity, with variation between highly cellular and sparsely cellular collagenous zones. The tumor was mainly composed of fibroblast-like spindle cells with patternless pattern of fascicles with branching large vessels. Mitotic activity was brisk (up to 40/10HPF) and focal tumor necrosis was found. Immunoreactivity for CD 34 was negative. The final diagnosis was malignant solitary fibrous tumor. The patient died after 4 month later. Key Words: Malignant solitary fibrous tumor 212