Gastric Outlet Obstruction Due to Gastric Amyloidosis Mimicking Malignancy in a Patient with Ankylosing Spondylitis

Amyloidosis is a group of disorders characterized by the extracellular accumulation of insoluble, fibrillar proteins in various organs and tissues. It is classified, on the basis of the identity of the precursor protein, as primary, secondary, or familial amyloidosis. Gastrointestinal amyloidosis usually presents as bleeding, ulceration, malabsorption, protein loss, and diarrhea. However, gastric amyloidosis with gastric outlet obstruction mimicking linitis plastica is rare. We report a case of gastrointestinal amyloidosis with gastric outlet obstruction in a patient with ankylosing spondylitis. The patient was indicated for subtotal gastrectomy because of the aggravation of obstructive symptoms, but refused the operation and was transferred to another hospital. Three months later, the patient died of aspiration pneumonia during medical treatment.