1Department of Ultrasonographic Laboratory, Kawasaki Naika Hospital, 2Department of Radiographic Laboratory, Kawasaki Naika Hospital, 3Department of Internal Medicine, Kawasaki Naika Hospital, 4Department of Radiology, Rinku General Medical Center, 5Department of Surgery, National Sanitarium Sengokusou Hospital, 6Department of Pathology, Minami Osaka Hospital
A 53-year-old woman was hospitalized by ambulance because of vomiting and severe abdominal pain. Physical examination disclosed tenderness on the periumbilical region, slight abdominal fullness, and a diminished bowel sound, but without muscular defense or ascites. An abdominal enhanced CT scan showed a thickening of the wall of the small intestine, dilatation of the lumen, and a slightly contrasting lobulated mass over the urinary bladder. These signs suggested a disturbance in circulation caused by a twist in the stalk of the polypoid mass. The ultrasonography showed a keyboard-like sign in the dilated lumen of the small intestine and a remarkably large mass of about 12 cm in maximum diameter on the lower abdominal region with a clear margin and heterogenous internal echogenicity. Color and power Doppler ultrasonographic study of the mass showed few color-flow signals but detected feeding-vessels connected to the intestinal vessels in the upper part of the mass. An obstruction was detected in the small intestine, a screw sign on gray-scale ultrasonography and a tornado-like vessel image on color Doppler ultrasonography. Clinical diagnosis was a strangulated ileus complicated by a twisted stalk of the polypoid mass in the small intestine. On surgery, the mass was found to originate orally 140 cm from the ileocecal junction; it measured 12×7×5 cm and had an extraluminal stalk on the opposite side of the mesenterium. Pathologic findings included a gastrointestinal stromal tumor, a so-called GIST, originating in the ileum. The microscopic findings included tightly arranged pleomorphic spindleshaped cells, and 11 mitotic figures were seen in 20 high-power fields on hematoxylin-eosin staining. Immunohistochemically stained the specimens reacted positively to CD 34, c-kit, and HHF 35, but negatively to vimentin, Desmin, and S-100 protein. Our diagnosis of malignant GIST associated with myogenic differentiation was based on this evidence. Color Doppler ultrasonography was useful for the detection of disturbed circulation caused by a twisted stalk.