Hemorrhagic Amyloid Bowel

Abstract

Purpose: Clinically apparent gastrointestinal (GI) involvement is a rare presentation of primary (AL) amyloidosis. Up to 60% of patients with secondary (AA) amyloidosis were found to have clinical GI involvement compared to only 1% involvement in AL amyloidosis group. Primary amyloidosis can present alone or with other plasma cell dyscrasias (PCD) like multiple myeloma or Waldenström's macroglobulinemia (WM). We present a case of lower GI bleeding secondary to AL amyloidosis to report a rare presentation of AL amyloidosis and broaden awareness of clinicians on primary amyloidosis as a possible cause of GI bleeding. A 67 year-old male with a history of WM presented with abdominal cramping and diarrhea of 1 day, followed by maroon stools of four to five episodes. He also reported about 10lb weight loss over the past six months. Three years ago, he had screening colonoscopy which was reportedly normal. His other medical problems include type 2 diabetes mellitus and dyslipidemia. On examination, he was hemodynamically stable, soft non-tender abdomen and on digital rectal exam only bright red blood was noticed. His hemoglobin was 8.1 g/dL, down from a reported level 10 g/dL three months prior to presentation. An Abdominal CT scan without contrast showed diffuse irregular thickening of the right colonic wall suspicious for colitis or lymphoma. A colonoscopy showed bright red blood throughout the entire colon and a large lumen obstructing blood clot verses a mass in the ascending colon which made difficult to pass the colonoscope. The patient had laparotomy which revealed a soft mesenteric lymphadenopathy and a diffusely ecchymotic ascending colon with multiple hemorrhagic nodules within the colon wall. Biopsies showed colonic mucosa with underlying marked vascular dilatation, inflammation with ischemic-type necrosis, hemorrhage with overlying active ulceration and reactive lymph nodes with no evidence of malignancy. The Congo red stain showed several areas of lymphoid and vascular tissues with acellular eosinophilic material consistent with extensive amyloid deposition. Dominant GI presentation in AL amyloidosis is deposition of amyloid in the intestinal wall, leading to thickening, polypoid protrusions and further resulting in constipation, mechanical obstruction, or chronic intestinal pseudo-obstruction. But rarely GI bleeding can be a sole presentation. Primary amyloidosis should be considered as a possible cause for GI bleeding especially in patients with prior history of PCDs despite its rarity.