A Rare Case of Bleeding Duodenal Arteriovenous Malformations in Association with Amyloid Enteropathy

Abstract

Amyloidosis is a rare disease caused by accumulation of abnormal amyloid fibrils within the extracellular matrix leading to structural and functional disruption of the involved tissue. Gastrointestinal (GI) involvement is seen in primary, secondary and dialysis related amyloidosis. AVM's (arteriovenous malformations) in association with amyloidosis are a rare cause of GI bleed. We report an unusual case of duodenal AVM's associated with gastrointestinal amyloidosis (AL), presenting as an acute upper GI bleed. An 82-year old Caucasian male with history of coronary artery disease and atrial fibrillation on anticoagulation, presented with a complaint of melena. Physical examination was significant for pallor. Laboratory investigation revealed iron deficiency anemia with a hemoglobin of 7.9 g/dL. Subsequent EGD showed thickened small bowel polypoidal mucosal folds with multiple AVM's in the second and third portions of the duodenum, few of which were bleeding actively. APC (Argon Plasma Coagulation) therapy of the bleeding AVM's was performed with resultant satisfactory hemostasis. Mucosal biopsies of the thickened duodenal folds were also performed. Histology revealed amyloidosis involving the muscularis mucosa and vessels, which displayed an apple green birefringence under polarized light microscopy using Congo Red stain (Figure 1).2010 Figure 1. (a, arrow) Thickened polypoidal mucosal folds (b, arrow) Multiple AVM's visualized in the duodenum (c, arrow) Actively bleeding AVM (d) Duodenal wall H&E stain showed homogenous eosinophilic deposits of muscularis mucosa and vessels, suggestive of amyloid enteropathy; (e, arrow). Positive Congo red staining of amyloid deposits in the vessel (f) Apple green birefringence (arrow) of Congo red stain under fluorescence polarized microscopy confirmed amyloid rich deposition.Further laboratory investigation revealed a negative urine immunofixation test for monoclonal free and ? light chains. Mass spectroscopy revealed AL type amyloidosis, however the workup for plasma cell dyscrasias (multiple myeloma/Waldenstorm macroglobulinemia) was negative. GI tract involvement occurs more often with AA amyloidosis rather than with the AL type. Patients with amyloid enteropathy can present with GI bleeding, the etiology of which is usually secondary to ischemia, mucosal ulcers, and submucosal hematomas. Rarely AVM's have been found to be associated with amyloidosis. Published data has shown such association as with gastric and pulmonary AVM's. This case demonstrates a rare presentation of GI bleed in the setting of amyloid enteropathy secondary to duodenal AVM's. This is the first reported case of bleeding duodenal AVM's with amyloidosis. Hence it is our recommendation, that the presence of AVM's with thickened or polypoidal small bowel folds should prompt the endoscopist to rule out amyloidosis.