Signet-ring cell carcinoma of the ampulla of Vater.

Signet-ring cell carcinoma (SRCC) of the alimentary canal is a variant of adenocarcinoma that has a poor clinical prognosis. SRCC of the ampulla of Vater is extremely uncommon with < 12 cases reported in the literature. SRCC of the ampulla of Vater occurs in an older age group (mean age 60 yr) when compared to SRCC of the stomach (under 45 yr), but is similar to SRCC of the large intestine. We report a case of SRCC of the ampulla of Vater with unusual histopathologic features in a 56-yr-old woman who presented with a small tumor at the orifice of the ampulla, associated with extensive lymphovascular invasion and multiple regional lymph node involvement.