Primary Gastrointestinal Amyloidosis With Multiple Myeloma

Abstract

Primary systemic amyloidosis (AL) is characterized by the deposition of fibrils composed of monoclonal light chains in the extracellular matrix of various organs including the gastrointestinal (GI) tract. A 53 year old African American female with history of hypertension presented with complaints of progressively worsening dysphagia and weight loss for the past 5 months. Recently, her dysphagia progressed from solids to liquids, leading to a 50 pound weight loss, associated with abdominal fullness, early satiety, and postprandial vomiting. Review of systems revealed dyspnea on minimal exertion and easy fatigability. She had no prior personal or family history of malignancy, renal failure or inflammatory conditions. She was found to have new anemia with a hemoglobin of 7.8 gm/dl, concerning for a GI malignancy. Esophagogastroduodenoscopy did not reveal any evidence of bleeding or esophageal or gastric masses, but showed generalized mucosal wall thickening in the stomach. The gastric biopsy showed vascular and stromal amyloid deposition, confirmed with Congo red stain (Figure 1) showing bright apple green birefringence under polarized light. Colonoscopy confirmed similar evidence of amyloid deposition. A bone marrow biopsy was obtained which showed evidence of advanced multiple myeloma (MM) (Figure 2), confirmed by electrophoresis showing elevated Kappa free light chains. An echocardiogram showed infiltrative cardiomyopathy with reduced ejection fraction. She was started on borteozomib and dexamethasone but ultimately developed intestinal obstruction requiring TPN, and palliative treatment was offered.Figure 1Figure 2AL due to any cause is a common disorder; however, primary GI amyloidosis (GAL) is found in approximately 8% of biopsy proven, and only 1% of clinically symptomatic patients with AL. Hepatic amyloidosis is more common than intestinal amyloidosis. 50% of GAL are seen in patients with chronic degenerative arthropathies (rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis), chronic renal failure, and multiple myeloma. GAL can present with symptoms of either GI bleeding, chronic intestinal dysmotility causing intestinal obstruction, malabsorption and/or protein-losing enteropathy. Diagnosis is obtained by biopsy of the GI mucosa deep enough to include lamina propria since apple green birefringence is best identified in the wall of blood vessels. Treatment is largely dependent on reducing the production of amyloid precursor and controlling the primary cause. A few case reports have shown improvement with experimental humanized anti-IL6 receptor antibody. GAL causes significant morbidity, but death is usually due to underlying cardiomyopathy, renal failure or advanced malignancy.