Abstract
Primary leiomyosarcoma of the mesentery is relative rare. To date, 9 cases with this disease diagnosed immunohistologically, including our present case, have been reported in Japan. We describe an immunohistologically diagnosed case of primary leiomyosarcoma of the small intestinal mesentery recently encountered at our facility. The patient was a male in his 70s. In June 2009, he visited the Department of Internal Medicine of our hospital, with a chief complaint of abdominal flatulence. A giant mass was palpable in the hypogastric region. Abdominal CT scans revealed a mass approximately 120 mm in size within the pelvis. Based on test results, a non-epithelial malignant tumor of retroperitoneal or mesenteric origin was suspected and the patient underwent surgical tumor resection. The tumor was found to have developed in the small intestinal mesentery, with subsequent invasion of the small bowel and urinary bladder. Histopathologically, spindle cells with intensely eosinophilic cytoplasm formed a complex array of bundles. The tumor cells were immunohistologically shown to be α-SMA and desmin positive and tested negative for c-kit, CD34 and S-100, thus allowing a diagnosis of leiomyosarcoma.
