A 48-year-old female patient with von Recklinghausen's disease was admitted to Kaohsiung Medical College Hospital due to massive hematochezia. The emergent mesentery arteriography revealed multiple hypervascular small intestinal lesions but no contrast extravasation. The endoscopic examination revealed a blood-filled small intestine with normal colonic mucosa. Laparotomy was carried out and multiple extraluminal masses on antimesenteric side of the small intestine were found. Segmental resection of the small intestine resulted in resolution of her symptom. The largest mass was diagnosed as leiomyosarcoma, and the others were diagnosed as leiomyoma. Histologically, differential diagnosis between leiomyosarcoma and leiomyoma is not clear cut, because it is based on a number of differentiating features. Surgical resection is the treatment of choice for intestinal leiomyosarcoma. The long-term follow-up of this patient is mandatory.