Gallstone obstruction of the pylorus.
D000368:Aged; D002769:Cholelithiasis / Q000150:complications* / Q000175:diagnosis; D004380:Duodenal Obstruction / Q000175:diagnosis / Q000209:etiology; D004724:Endoscopy; D006801:Humans; D008297:Male; D011708:Pylorus; D013272:Stomach Diseases / Q000175:diagnosis / Q000209:etiology