1883 A Surprising Biopsy Result: Primary GI Amyloidosis

Abstract

INTRODUCTION: Amyloidosis is the deposition of insoluble extracellular protein fragments. Gastrointestinal (GI) amyloidosis often presents with abdominal pain, weight loss, diarrhea and GI tract bleeding. Diagnosis is confirmed with congo red stain showing green birefringence under polarized light. Treatment differs for each type of amyloidosis; thus, accurate diagnosis is crucial for successful treatment. We present a case of primary GI amyloidosis presenting with new onset microcytic anemia. CASE DESCRIPTION/METHODS: A 73-year-old African American male with past medical history of hypertension, hyperlipidemia and erythrocytosis secondary to obstructive sleep apnea was being seen for a routine follow up by his hematologist. The erythrocytosis was previously evaluated with JAK2 and EPO testing; both negative. He was being treated with periodic phlebotomies, remaining asymptomatic. However, on this particular office visit he was found to have a new microcytic anemia, for which gastrointestinal workup was recommended. Upon evaluation by the gastroenterologist, esophagogastroduodenoscopy (EGD) and colonoscopy were performed. The EGD showed a non-obstructing Schatzki ring, erosive gastritis, a gastric ulcer at the pre-pyloric region, duodenitis and multiple superficial duodenal erosions. The colonoscopy showed a polyp in the cecum and descending colon and diverticulosis. Biopsies were taken during the procedures and returned with amyloid depositions, consistent with GI amyloidosis in the duodenum, stomach and descending colon. A few weeks later, the patient developed rectal bleeding and passage of clots. Repeat colonoscopy was done which showed diffuse large ulcerations in the sigmoid and descending colon. Again, pathology confirmed amyloid depositions in the GI mucosa. Given these surprising findings, his hematologist performed a bone marrow biopsy which showed normocellular marrow with trilineage hematopoiesis, negative for malignancy. Myeloma FISH panel was positive for 11.14 translocation. The patient was diagnosed with light chain myeloma with amyloidosis (AL subtype) involving the GI tract for which steroids and chemotherapy were initiated. DISCUSSION: Our case discusses a rare diagnosis of primary GI amyloidosis. This patient is unique because GI amyloidosis was his primary presentation without any cardiovascular or renal manifestation. Although amyloidosis is rare, it is important to have a high index of suspicion when evaluating new onset anemia of unknown origin.