Malignant plasmacytic ascites. A report of two cases and a review of the literature.

Two patients with ascites due to peritoneal involvement by multiple myeloma are reported and seven previously described cases of plasmacytic ascites are reviewed. In all nine cases, ascitic fluid contained large numbers of bizzare, immature plasma cells. Although the cells were often difficult to characterize by light microscopy, they could be rapidly identified as malignant plasma cells by immunofluorescent demonstration of monoclonal, intracellular immunoglobulin as performed in one of the patients. This rare extramedullary complication of plasma cell neoplasia has been unresponsive to therapy and rapidly fatal, with a median survival of 2 months.