Ampullary adenomyoma presenting as acute recurrent pancreatitis.

Adenomyoma is a term generally applied to nodular lesions showing proliferation of both epithelial and smooth muscle components. Despite its benign nature, ampullary adenomyoma is usually presented as biliary obstruction. Most cases are misdiagnosed as carcinoma or adenoma by preoperative endoscopic or radiologic procedure. Therefore, it is frequently treated with extensive surgery. To our knowledge, this is the first reported case in English literature of adenomyoma located in the peripancreatic orifice resulting in intermittent pancreatic duct obstruction and recurrent pancreatitis diagnosed by the endoscopic piecemeal resection.