S2910 Symptomatic Gastrointestinal Amyloidosis in a Patient With Systemic AL Amyloidosis

Abstract

INTRODUCTION: Gastrointestinal (GI) amyloidosis is a rare protein deposition disorder that can be limited to the GI tract but is most often a manifestation of systemic amyloidosis. While it can be asymptomatic, typical presentations include dysmotility, malabsorption, bleeding and protein-losing gastroenteropathy. GI amyloidosis is most commonly in the esophagus, duodenum, stomach and rectum. The diagnostic gold standard is tissue biopsy with positive Congo red staining, usually from the rectum (sensitivity, 75-85%) or duodenum. CASE DESCRIPTION/METHODS: A 57-year-old woman with systemic amyloid light-chain (AL) amyloidosis complicated by restrictive cardiomyopathy, heart failure and junctional bradycardia requiring a pacemaker, and treated with bortezomib and dexamethasone with good response, presented to the hospital with recurrent constipation, nausea, vomiting and abdominal discomfort. Abdominal radiographs and CT scan demonstrated dilation of the cecum to 7.9 cm, concerning for ileus, but no obstruction (Figure 1). She was diagnosed with likely colonic pseudoobstruction, treated with neostigmine, and discharged on a regimen of antiemetics and prokinetics. Soon after, she was re-admitted with rectal bleeding; colonoscopy showed normal-appearing mucosa and polyps (Figure 2), with a large hemorrhoid as the likely source. Subsequently, she was re-admitted for a heart failure exacerbation; she was considered for heart transplant as her disease was believed to be in remission but had persistent poor oral intake, nausea and constipation. Endoscopy was notable for a gastric phytobezoar and duodenal ulcers; gastric, duodenal and rectal biopsies with Congo red stain confirmed the diagnosis of GI amyloidosis. She was started on ixazomib and dexamethasone, with improved GI symptoms and only mild dysmotility seen on a gastric emptying study, and is pursuing heart transplantation. DISCUSSION: GI amyloidosis is rare but has important clinical and prognostic implications. Our patient presented with a range of vague GI symptoms and non-specific radiographic and gross endoscopic findings. Maintaining a high index of suspicion and obtaining mucosal biopsies with Congo red staining early in the course avoids delay in diagnosis and symptom progression. Upon diagnosis of GI amyloidosis, this patient was treated with chemotherapy, which targeted the underlying cause of her GI symptoms, resulting in sufficient improvement. In this case, the patient’s diagnosis of GI amyloidosis was key to her consideration for cardiac transplant.Figure 1.: Abdominal radiograph showing increased gaseous distension of the colon compatible with ileus. No evidence of obstruction.Figure 2.: Colonoscopy showing normal appearing mucosa and multiple polyps in the descending colon.