Localized malignant peritoneal mesothelioma containing rhabdoid cells.

A case is presented of localized malignant peritoneal mesothelioma appearing as a liver neoplasm. The patient underwent tumor resection but developed a recurrent growth and died 10 months after the initial surgery. The primary tumor showed sarcomatous features with rhabdoid cells. Examination revealed the presence of hyaluronic acid, co-immunoreactivity for cytokeratin epithelial membrane antigen and vimentin, cellular contacts with small desmosomes, and intracytoplasmic lumina. These findings supported the mesothelial nature of this tumor. The recurrent tumor was composed of predominantly tubulopapillary proliferation. It was concluded that the present tumor was a localized malignant mesothelioma of a biphasic type showing a predominantly sarcomatous component in the primary tumor.