Primary lymphoma of the ampulla of vater

A 57‐year‐old woman was investigated for obstructive jaundice with endoscopic retrograde cholangiopancreaticography that showed a tumor at the ampulla of Vater. A Whipple's procedure was performed. A protuberant tumor was present at the ampulla of Vater in the background of multiple mucosal polyps in the duodenum. Light microscopy revealed a diffuse non‐Hodgkin's lymphoma with centrocytelike cells forming lymphoepithelial lesions and infiltrating the sphincter of Oddi. The duodenal polyps were hyperplastic lymphoid follicles with reactive germinal centers. Immunohistochemical staining characterized the tumor as a B‐cell neoplasm with IgA heavy‐chain and lambda light‐chain restrictions. Complete remission of the disease occurred after surgery. The clinical, histologic, and immunohistochemical features of this lymphoma are suggestive of histogenetic derivation from mucosal‐associated tissue.