抄録
Atypical fibrous histiocytoma is classified as an intermediate type of fibrous histiocytoma. A five year-old girl had a painless tumor in her right lumber region following blunt injury on this site. Computed tomography revealed a subcutaneous tumor extended to the major psoas muscle. An extensive excision of the tumor and surrounding normal tissues were carried out. Histological examination revealed atypical fibrous histiocytoma. Neither postoperative irradiation nor adjuvant chemotherapies has been made. She is doing well without any sign of recurrence for one and a half years after the operation.