Systemic AL amyloidosis with multiple submucosal hematomas of the colon: a case report and literature review.

Amyloid light-chain (AL) amyloidosis rarely causes colorectal submucosal hematoma. A 76-year-old man presented with a complaint of bloody stool. An initial colonoscopy revealed ulcerative lesions in the descending colon, leading to a diagnosis of ischemic colitis. One month later, he presented with cardiac failure, suspected cardiac amyloidosis, and underwent a second colonoscopy. Although it revealed multiple ulcerative lesions from the ascending to transverse colon, biopsy samples did not confirm amyloid deposition. He underwent a third colonoscopy 3 weeks later due to recurrent bloody stool. It showed multiple submucosal hematomas from the ascending to descending colon concomitant with ulcerative lesions in the descending colon and multiple elevated lesions in the sigmoid colon. Biopsy samples confirmed amyloid deposition. Using a systemic search, multiple myeloma with AL amyloidosis was diagnosed. Colorectal submucosal or intramural hematomas are conditions usually encountered in trauma, antithrombotic use, or coagulation disorders. Based on our review of the literatures, we identified several differences between colorectal intramural hematoma caused by amyloidosis and those caused by other etiologies. We believe that amyloidosis should be considered when relatively small and multiple colorectal hematomas, not restricted to the sigmoid colon, and with concomitant findings of erosions and ulcers, are observed.