Lymphatic obstruction in carcinomatous ascites

The i.p. inoculation of C3H mice with 5 times 10-6 cells of a transplantable ovarian carcinoma invariably evokes accumulation of large amounts of ascitic fluid. Histological and pharmacotherapeutic studies indicate that obstruction to peritoneal lymphatic drainage is a key factor in the formation of carcinomatous ascites in this model. In the early stages of ascites formation, an intense inflammatory reaction appears to occlude the condusts that connect the peritoneal cavity to the subdiaphragmatic lymphatic plexus. This inflammatory reaction, elicited by the presence of tumor cells within the peritoneal cavity, can be inhibited with high-dose systemic corticosteroid therapy. Ascitic fluid accumulation in animals so treated is markedly retarded. Tumor cells do not gain access to lymphatic capillaries draining the peritoneal cavity until ascitic fluid accumulation is massive. Systemic anticoagulation with heparin or sodium warfarin does not prevent lodgment of tumor cells within these lymphatic capillaries, nor does it alter the pattern of ascitic fluid accumulation. Various considerations suggest that excess production of ascitic fluid is not a likely pathogenetic factor in murine carcinomatous ascites.