[A case of ileal leiomyosarcoma, difficult to differentiate from retrovesical tumor: report of a case].

A case of ileal leiomyosarcoma which was preoperatively diagnosed as a retrovesical tumor in a 41-year-old male patient was reported. He consulted our department with a complaint of tenesmus ani. CT, MRI and ultrasonography showed a mass in the retrovesical space which was palpable superior to the prostate in anal digital examination. Intraoperatively, the tumor was found to originate from the ileum, 250 cm from the ileocecal joint (Bauhin's valve). It is difficult to make diagnosis of leiomyosarcomas of small intestine preoperatively. Thirty-eight cases of leiomyosarcoma of small intestine reported in the recent 5 years in Japan are reviewed and discussed.