Two sera obtained from four healthy blood donors, which caused non-A, non-B post-transfusion hepatitis in two recipients, were experimentally inoculated into nine marmosets. Three of seven marmosets developed acute hepatitis characterized by the elevation of serum concentrations of glutamic pyruvic transaminase (GPT) and/or isocitric dehydrogenase (ICD) 8-11 weeks after inoculation. Four of seven showed histopathological changes of acute hepatitis in liver biopsy specimens during the biochemically acute phase. In electron microscopic examination, attached membrane-like structures, which consisted of two-unit membranes of two neighboring endoplasmic reticula with electron-dense material between them, were noted in cytoplasm of hepatocytes during the acute phase of hepatitis. Furthermore, acute-phase sera obtained from two animals were inoculated into four additional marmosets, and non-A, non-B hepatitis was successfully passaged in two of them. The results of this study indicate that certain species of marmoset monkeys are susceptible to human non-A, non-B hepatitis agents and provide a useful animal model for non-A, non-B hepatitis.

A case of pulmonary adenocarcinoma, which was initially manifested as a gastric submucosal tumor, is presented. Endoscopy showed a submucosal tumor in the fundic region in a 79‐year‐old Japanese woman. Initial biopsy specimens of the stomach revealed atypical spindle cell proliferation, suggesting primary leiomyosarcoma of the stomach. However, biopsy specimens obtained one year later were diagnosed as malignant lymphoma or malignant histiocytosis of the stomach. Autopsy revealed a large necrotic lesion in the right S8 region with metastases in multiple organs. Microscopy demonstrated well to moderately differentiated adenocarcinoma containing spindle or pleomorphic sarcomatous elements. Metastatic nodules including the gastric tumors all showed sarcomatous elements with no epithelial component. Immunohistochemistry showed positive reactions for keratin, epithelial membrane antigen, and carcinoembryonic antigen in areas of carcinoma, whereas most of the sarcomatous elements revealed no positivity for any of the antibodies used, except for focal keratin and EMA positivity in the primary site. This is a rare case of pulmonary adenocarcinoma with sarcomatous elements discovered as a gastric tumor at initial diagnosis, resulting from metastasis of the sarcomatous element in the submucosa.