A Case of Leiomyoma in the Small Intestinal Mesentery

Leiomyoma of the small intestinal mesentery is very rare, and we report only the 15th case, to our knowledge, in the Japanese literature. A 66-year-old man with a full sensation of the abdomen and constipation was hospitalizedfor an intraabdominal mass. Physical examination showed a 14×11×14cm elastic, hard, movable smooth tumor generating pain upon pressure palpable in the left lower abdomen. Ehography, CT, and MRI showed a well-defined, lobular tumor with a heterogeneous internal structure. A small-intestine series showed only pressure to the small intestine due to the tumor. Angiography showed a dilated, crooked ileocolic artery. Upon laparotomy, the tumor was present in the small intestinal mesentery and had no invasive lesion. Partial intestinal excision revealed a 14×11×14cm lobular, elastic, hard tumor. Histopathological and immunohistologicalstudies showed c-kit (-), CD34 (-), S100 (-), and desmin (+). Leiomyoma arising in the small in-testinalmesentery was the definitive diagnosis. The postoperative course was uneventful and he has been free from recurrence, but 10%level in MIB 1 level index requires careful follw-up.