Malignant peritoneal mesothelioma with massive foamy cells. Codfish roe-like mesothelioma.

An autopsy case of a 45 years old Japanese female with malignant masothelioma showing peculiar stromal change was presented. The tumor had occupied the abdominal cavity around the uterus and both ovaries, and was diagnosed as a malignant peritoneal mesothelioma of epithelial type. The characteristic feature of the tumor was that the foam cells, which contained abundant amount of lipid droplets in the cytoplasm, and were thought to be histiocytes, massively occupied the stroma of the papillary tumor. Macroscopically, the tumor simulated a codfish roe. To our knowledge, no case of this sort of appearance of mesothelioma has ever been reported.