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.