Ascites as a presenting feature of relapsed multiple myeloma. Report of a case diagnosed by aspiration cytology.

A 68-year-old woman with IgG-type multiple myeloma (MM) in remission and a chief complaint of ascites was found to have peritoneal fluid involvement by myeloma cells on cytologic study. There are only a few reports describing the cytologic features in patients presenting with ascites as the first manifestation of relapsed MM. IgG myeloma, however, is one of the rarest types. The patient had had pancreatic involvement months before her presentation with ascites, which itself is a rare manifestation of relapsed MM. Cytologic smears of ascitic fluid showed isolated and incoherent groups of cells with plasmacytoid features. To recognize myeloma as a cause of ascites is important because it may respond well to therapy. Aspiration cytologic study can be considered a useful method for follow-up and diagnosis of MM relapse even without a biopsy.