Secondary intestinal amyloidosis presenting intractable hematochezia: a case report and literature review.

Amyloidosis is characterized by an extracellular deposition of insoluble fibrils. Amyloid deposition caused various clinical symptoms associated with affected organs. Secondary amyloidosis without renal involvement and chronic inflammatory conditions is rarely reported. We experienced a case of secondary intestinal amyloidosis presented with recurrent hematochezia and abdominal pain in a 54-year-old male. Sigmoidoscopy and abdominal computed tomography (CT) presented ischemic colitis and necrosis of whole colon. On microscopically, pinkish amorphous materials were infiltrated in the lamina propria and the thickened submucosal vessel walls in colon. The apple-green birefringence with polarized light on Congo red stain was demonstrated in the lamina propria and submucosal vessel walls. The deposits were positive for amyloid A and κ and negative for λ. The echocardiography and cardiac MRI findings showed infiltratives cardiomyopathy involving amyloidosis. Despite of conservative treatment, ischemic colitis and hemorrhage were aggravated and the patient expired.