Solitary amyloidosis of the sigmoid colon featuring submucosal tumor caused hematochezia.

A previously a healthy 64-year-old woman complained of a two-week history of hemorrhaging upon defecation. The laboratory and urinalysis findings were normal, and no serum or urine M components were detectable on protein electrophoresis. An air contrast barium enema revealed an elevated lesion measuring -20 mm in diameter with a smooth surface and a depression in the sigmoid colon. Colonoscopy revealed a red colored and congested tumor. The exposed surface of the submucosal tumor (SMT) center was somewhat yellow in color and covered with fuzz. All other portions of the colon were normal. The endoscopy and double-contrast barium revealed a normal upper gastrointestinal tract and a normal small intestine, respectively. A histopathological evaluation of a biopsy specimen obtained from the SMT suggested amyloid deposition. However, the other biopsy specimens of the esophagus, stomach, duodenal bulb, second portion of the duodenum, terminal ileum and other portions of the colon demonstrated no amyloid deposition. Colonoscopic ultrasonography (US) revealed the hypoechoic, homogeneous SMT to be mainly localized within the submucosa. An endoscopic submucosal resection (EMR) of the solitary amyloidosis was performed and the immunohistopathology revealed the entire SMT to consist of amyloid light chain kappa amyloid deposition. We considered that the US followed by EMR contributed to the precise diagnosis of solitary amyloidosis and the treatment of hematochezia caused by a solitary area of amyloidosis within the sigmoid colon.