Abstract
A 53-year-old man was seen at the hospital because of a 2-week history of abdominal pain. Abdominal CT scan revealed a sausage-shaped pattern, telescoping of a segment of the right transverse colon into the distal side, and intussusception of the transverse colon was diagnosed. Colonoscopy demonstrated a type 1 tumor 3 cm in diameter in the transverse colon at the hepatic flexure. Endoscopic pneumatic reduction was successful to reduce the intussusception. A biopsy of the tumor showed only fibrosis and inflammatory change, but a possibility of malignancy could not be ruled out. We performed elective right hemicolectomy with lymph node dissection. Histopathology revealed nodular proliferation of spindle-shaped cells with mitotic activity and dyskaryosis from the muscular layer to the submucosal layer. On immunohistochemistry, the tumor cells were not immunoreactive for c-kit and CD34 and immunoreactive for desmin and α-SMA. The final diagnosis was leiomyosarcoma.
Since 2001 there have been only nine reported cases of leiomyosarcoma of the large bowel diagnosed by immunohistochemical staining in Japan, but no cases of the disease associated with intussusception like this case have been reported. This case is considered to be very rare.
