Abstract
A 3-year-old Japanese-black cow had malignant mesothelioma on the pleura and granulosa cell tumor of the left ovary. The pleural surface was disseminated with numerous small neoplastic nodules, and the tumor cells were immunohistochemically positive for cytokeratin and negative for vimentin and CEA, while cultured epithelioid cells derived from the tumor were positive for vimentin. The left ovary was entirely replaced by a neoplastic growth showing insular and follicular patterns, and the neoplastic cell clusters with some inter cellular spaces were separated by connective tissue septa. The tumor cells were positive for vimentin and negative for cytokeratin and CEA.
