So-called peritoneal implants of ovarian carcinomas. Problems in differential diagnosis.

The aim of this paper is the differential-diagnostic distinction of peritoneal 'implants' of serous ovarian tumours from morphologically similar lesions in the peritoneum. The authors investigated 22 cases of ovarian carcinomas, 'implants' of ovarian carcinomas, reactive mesothelial proliferates, endosalpingiosis, benign and malignant mesotheliomas, as well as papillary carcinomas of the pelvic peritoneum with conventional histological stainings and immunohistochemical methods (immunoperoxidase, ABC method). The cells of almost all mentioned lesions express cytokeratin, only the cells of the reactive mesothelial proliferates are partially keratin-negative. CEA was not detected in any of the lesions. Alpha-1-antitrypsin was present in the cells of some ovarian carcinomas and their implants. Lysozyme was found focally in some ovarian carcinomas and in some reactive mesothelial proliferates. An exact differentiation of peritoneal 'implants' as metastases of ovarian carcinomas or autochthonous neoplasias in the course of multifocal tumour development is not possible on the basis of our immunohistochemical findings.