Establishment of a novel model of peritoneal carcinomatosis of the peritoneal extension type.

AIM: Patients with scirrhous carcinoma of the gastrointestinal tract frequently develop peritoneal carcinomatosis-particularly of the peritoneal extension type (PET), which has a bad prognosis. We developed a novel animal model, suitable for testing treatments for PET. MATERIAL AND METHODS: In order to develop the model, we scraped the entire peritoneum of Fischer 344 rats with sterile cotton swabs and injected 1 × 10(6) cells of the RCN-9 cell type into the peritoneal cavity. RESULTS: In the novel experimental model, RCN-9 cells adhered only to the exposed basement membrane. The submesothelial layer and fibroblasts in the submesothelial layer grew and increased to a maximum at day 7, then decreased during late-phase peritoneal carcinomatosis. At day 14, RCN-9 cells coated the peritoneum in a manner similar to PET. CONCLUSION: We successfully established a novel animal model of peritoneal carcinomatosis that mimics clinicopathological features of PET. Fibroblasts in the submesothelial layer potentially play an important role in peritoneal carcinomatosis.