Combined choriocarcinoma and yolk sac tumor arising in Barrett's esophagus.

A patient with primary adenocarcinoma with yolk sac and trophoblastic differentiation occurring in Barrett's esophagus is reported. Yolk sac differentiation at this site has not been described previously. The diagnosis of germ cell differentiation initially was suggested by the finding of elevated serum tumor marker levels. The patient experienced disease remission after cytotoxic chemotherapy. Germ cell differentiation may be difficult to identify in small biopsy samples, which may not be representative of the tumor as a whole. The finding of germ cell differentiation defines therapy and predicates for a relatively good prognosis, which is contrast to adenocarcinoma. Because of the significance of germ cell differentiation in the selection of appropriate therapy, immunostaining for germ cell tumor markers is suggested in all patients with adenocarcinoma who are younger than 50 years.