We report a case of peritoneal malignant mesothelioma in a 66-year-old man, comparing ascites aspiration cytology and the tumor imprint at autopsy. Cytology showed papillary clusters of epithelioid cells with hyperchromatic nuclei and prominent nucleoli. Autopsy showed mainly atypical spindle cells intermingled with epithelioid cell islands. Findings of imprint cytology reflect the histological structure making it useful in differentiating mesothelioma from adenocarcinoma.
