Leiomyosarcoma of the duodenum in a 10-year-old boy.

An unusual incidence of a duodenal leiomyosarcoma in a 10-year-old boy is presented. The corrected diagnosis was made after a 27-month course of occult gastrointestinal bleeding, vague abdominal complaints, and anemia. Gastrointestinal radiography and upper gastrointestinal endoscopy were useful in localizing the lesion. The tumor was removed at exploratory surgery by simple excision. On frozen section, the tumor was thought to be benign, but fixed microscopic histological sections revealed a well-differentiated, malignant smooth muscle tumor. The presentation of this tumor in a child is compared to previously reported cases in adults, and the biological and clinical characteristics of malignant smooth muscle tumors of the gastrointestinal tract are reviewed.