Leiomyosarcoma of the small intestine presenting as a pelvic mass.

We present a challenging case of differential diagnosis of leiomyosarcoma of the small intestine in a patient presented with a pelvic mass. This 43-year-old Japanese woman complained of hypermenorrhea and was diagnosed as myoma uteri. She underwent partial resection of the ileum with a primary end-to-end anastomosis, omentectomy, and appendectomy, as well as a simple hysterectomy and bilateral salpingo-oophorectomy. CT and MRI indicated an intestinal tumor at the gaseous site. The histological diagnosis was leiomyosarcoma of the small intestine and leiomyoma of the uterus. Although such leiomyosarcomas are rare, they can appear as pelvic masses and must be differentiated from gynecologic disease. Preoperative CT and MRI of the abdomen were useful in obtaining the diagnosis.