Peritoneal mesothelioma, a rare cause of malignant ascites

History and clinical findings: A 56-year-old patient (case 1) with recurren t haemorrhagic ascites for one year was admitted to our hospital for furthe r investigation. Besides massive ascites he did not show abnormal physical signs. In addition, two 45-year-old patients were admitted (case 2 and 3)wi th clinical signs of acute abdomen - one having muscular guarding in the ep igastric angle, the other in the right lower quadrant. All 3 patients did n ot have serious illnesses in the past; the first 2 patients had occupationa l asbestos exposure. Investigations: In patient 1 the ultrasound did not reveal abnormal finding s besides ascites. Patients 2 and 3 underwent explorative laparotomy. Diagnosis, treatment and course: In the first case a diagnostic laparoscopy revealed diffuse tumor proliferations with nodular formations over the ent ire peritoneum - histologically a malignant peritoneal mesothelioma of the epithelial subtype. Patient 2 showed intraoperatively metastatic spread of tumour formations with infiltration of the peritoneum and transverse mesoco lon. The histologic finding was similiar to that in the first case. Patient 3 had a perforated sigma diverticulitis which was treated by resection of the sigmoid. Incidentally a well differentiated papillary peritoneal mesoth elioma was found in the resected specimen. The first two patients were trea ted with cc-interferon subcutaneously resulting in a decrease of ascites pr oduction. Because patient 3 showed neither ascites nor evidence for maligna ncy no interferon was administered. Conclusion: In case of haemorrhagic ascites of unknown cause a histological clarification by either laparoscopy or laparotomy is mandatory. Immunomodu lation with interferon may be a promising approach.