[Pathologic and anatomic evidence of peritoneal metastases].

Peritoneal metastases are secondary tumours of the peritoneum and the most common tumours at this location. Ovarian carcinoma, colorectal cancer, and gastric cancer are the most frequent ones that show peritoneal involvement, along with carcinomas of the pancreas, gallbladder, uterus, and lung. Primary tumours originating in the peritoneum such as malignant peritoneal mesothelioma, primary peritoneal carcinoma, and benign peritoneal tumours along with inflammatory and reactive lesions must be differentiated from peritoneal metastases. Especially in cancer of unknown primary tumour, the discrimination between primary peritoneal tumours and peritoneal metastases is difficult and often requires immunohistochemical identification.