A signet-ring cell carcinoma of the ampulla of Vater.
 We describe a variant of carcinoma of the ampulla of Vater, which, to our knowledge, has not been previously described.
 Classic signet-ring cells represented the predominant cell type, and were admixed with more poorly differentiated tumor cells that were chromogranin positive.
 These findings raise the possibility of an amphicrine tumor of the ampulla.
