Malignant fibrous histiocytoma originating from the mesorectum: a case report

Malignant fibrous histiocytoma (MFH) is a common sarcoma affecting soft tissues of the body, especially of the extremities or trunk. Prognosis of the abdominal MFH is usually poor.

A 52-year-old female presented to our surgical outpatient clinic with a lower abdominal tumor that had been gradually increasing in size. Clinical examination revealed a firm, irregularly surfaced, fixed, painless, child-head-sized tumor located in her lower abdomen. Computed tomography (CT) and magnetic resonance imaging (MRI) of the abdomen revealed a polycystic tumor at the lower abdomen which was 15 × 13 × 11 cm in diameter and encased the colorectum to the left back side. A barium enema and a colonoscopy showed direct invasion to the rectum. In 2001, the tumor had been excised along with a low anterior resection of the rectum because of direct invasion. The origin of this tumor was the mesorectum. The weight of the excised tumor was 1,500 g, including 800 ml of a brown fluid. A histopathological diagnosis revealed a common type of MFH, in which mitotic figures are frequently seen.

This patient has survived without recurrence, for approximately 8 years since the completed tumor resection. It is important to obtain a complete resection during the MFH treatment.