上顎に発生した低悪性型筋線維芽細胞肉腫の1例

抄録

Low-grade myofibroblastic sarcoma is an uncommon neoplasm of atypical myofibroblasts with fibromatosis-like features. The lesion has only been characterized in the last two decades, and the concept of neoplastic myofibroblasts remains controversial. We encountered a patient with low-grade myofibroblastic sarcoma of the maxilla.
A 70-year-old woman was referred to our hospital because of swelling of the anterior maxilla. She had undergone repeated surgical procedures of the lesion at other hospitals. The tumor invaded the hard palate, nasal cavity, bilateral maxillary sinus, and cheek skin. The biopsy specimen showed a low-grade myofibroblastic sarcoma, and she underwent wide resection of the lesion and reconstructive surgery using a free forearm flap. Histologic examination revealed diffuse, fascicular proliferation of spindle cells with focal cellular atypia. The tumor cells showed positive reactions for α-SMA and vimentin, which indicated differentiation to myofibroblasts, and the lesion was diagnosed as a low-grade myofibroblastic sarcoma. The patient is free from tumor 13 months after surgery.