Immunocytochemical presentation of alpha-fetoprotein-producing gastric cancer in ascitic fluid: a case study.

A case of primary gastric cancer without hepatic metastasis showing extremely high alpha-fetoprotein (AFP) levels is reported. This case illustrates the application of the immuno-peroxidase technique to ascitic fluid cytology. Papanicolaou-stained smears of the ascites permitted the diagnosis of a metastatic carcinoma. A positive reaction to AFP was demonstrated in the tumor cells in the ascitic fluid cellular samples as well as in the paraffin-embedded tissue section of the primary gastric carcinoma. Rising AFP levels were also detected in ascitic fluid. AFP fractionation using lectin-affinity-crossed-line immunoelectrophoresis showed the hepatic rather than yolk sac type. Reports of such occurrences are few; no study, to the best of our knowledge, has previously documented cytological and immunocytochemical diagnosis in ascitic fluid. AFP-producing gastric cancer should be considered in the differential diagnosis.