超音波検査技術

A woman in her 90s was admitted to our hospital owing to the complaint of difficulty in moving her body after experiencing a fall at home. Further examination with abdominal plain computed tomography (CT) revealed pancreatic duct dilatation at the pancreatic body and tail. However, no blockage was observed in the pancreatic head. Further examination of the dilatation with abdominal ultrasound showed the presence of hypoechoic lesions from the beginning of the portal to the confluence of the superior mesenteric, inferior mesenteric, and splenic veins, which subsequently resulted in inferior mesenteric vein dilatation. Colored Doppler ultrasound indicated the presence of bloodstream in these lesions, which were thought to be tumor embolism. Furthermore, a hypoechoic tumorous lesion, 30 mm in size, was detected and was characterized by irregular shape, internal heterogenicity, and localized wall thickening of the sigmoid colon. Therefore, sigmoid colon cancer associated with tumor embolism was suspected. Contrast CT also demonstrated similar findings. Colonoscopy with bioptic examination was performed, and the tumorous lesion in the sigmoid colon was diagnosed as moderately differentiated adenocarcinoma.

Colon cancer invades the mesenteric vein through vessel invasion in the intestinal wall and metastasized to the liver via the portal vein. As tumor embolus formation requires a certain amount of time, it is very rarely observed as the identifiable tumor embolus in the mesenteric vein without liver metastasis by ultrasound.

In this report, we encountered a case of sigmoid colon cancer with tumor embolism, successfully detected via ultrasound examination, in the mesenteric vein.