Abstract
Here we report a case of AL-type amyloidosis with pyloric stenosis. A 73-year-old man with mild heart failure visited our hospital for anorexia and weight loss. He was given a diagnosis of severe pyloric stenosis after upper gastrointestinal endoscopy. However, mucosal irregularity remained very slight, and only mild erosion and redness were seen. There were no mucosal changes suggestive of an ulcer or malignancy, and a biopsied specimen had normal histopathological findings. The patient's symptoms were unresponsive to conservative management, so a distal gastrectomy was performed. Microscopic examination by hematoxylin-eosin staining of the resected specimen showed only mucosal atrophy and a thickened proper muscle, but the specific etiological details were not known. His heart function worsened and amyloidosis was suspected as a cause. A recheck of the surgical specimen using Congo Red stain revealed AL amyloid deposits in the muscularis mucosa, tunica muscularis, and vascular wall. Amyloidosis can cause pyloric stenosis, and it is necessary to consider it as a differential diagnosis of pyloric stenosis.
