Endorectal ultrasound and leiomyosarcoma of the rectum.

Leiomyosarcomas of the rectum are uncommon neoplasms accounting for fewer than 1% of all malignancies of the colon and rectum. Approximately 215 cases have been described in the literature. Distinction from leiomyoma is often difficult, but regarding dignity is important. The case reported is that of a 68-year-old man in whom a 2.2-cm rectal mass covered by mucosa was diagnosed by rectoscopy and endorectal ultrasound. After treatment by wide local excision the histological specimen revealed a low-grade, highly differentiated leiomyosarcoma. Due to the lack of a large series of this disease, there is disagreement over the therapeutic strategy. At the moment a selective treatment approach seems to be the most frequently advocated. Large tumors and those extending beyond the rectal wall are treated by radical surgical resection. Leiomyosarcomas less than 2.5 cm in size and confined to the bowel wall can be treated by wide local excision. Endosonography can provide exact assessment of tumor size and expansion and is of great value in selecting the appropriate treatment.