[Histopathological and immunohistochemical studies in hepatoid adenocarcinomas of the stomach]

To clarify the pathomorphology and the characteristics of clinical biological behaviors in hepatoid adenocarcinoma of the stomach (HAS), the clinical data of 24 HAS cases were reviewed and the specimens studied with light, electron microscopy and immunohistochemistry methods. The results show that HAS was more often found in middle aged and elderly people, and their serum alphafetoprotein (AFP) levels were significantly high. Among the 16 deceased cases, 12 died within one year and the mean survival period after operation was 10 months, only one of the 24 cases was early stage carcinoma, all others were of the advanced stage. Vessels were invaded in 18 cases (75%), metastasis to the regional or distant lymph nodes in 22 cases (91.7%) and liver metastasis in 14 cases (58.3%). HAS is a highly malignant tumor with poor prognosis. The tumors were composed of two different but closely related hepatoid and adenocarcinomatous areas. The tumor cells in the hepatoid region possess many features of hepatic cell carcinoma, such as abundant eosinophilic or clear cytoplasm, PAS positive hyaline globules in both intra- and extracellular spaces. AFP positive staining, intracytoplasmic bile, glycogen granules and intercarcinocyte bile canaliculus. Microvilli with intestinal epithelial type were found not only in adenocarcinoma areas but also in hepatoid areas. An indication that the HAS was differentiating into hepatic cell and intestinal epithelial types. We conclude that HAS possesses similar pathomorphologic pattern and clinicobiological behaviors of hepatic cell carcinoma and HAS should be classified as a special subtype of gastric carcinoma.