Pseudomyxoma peritonei: a cytohistopathologic study of nine cases

Cytologic examination of seven peritoneal fluids from nine patients with pseudomyxoma peritonei revealed papillary clusters and isolated neoplastic cells. In all patients, one or both ovaries were replaced by proliferating (borderline) mucinous epithelial tumors of grade I-II intestinal type while three patients had synchronous appendiceal tumors of similar morphologic appearance. Four of the nine patients demonstrated positive correlation between the presence of neoplastic cells in the ovarian interstitial mucin (pseudomyxoma ovarii), the extraovarian peritoneum, and the free peritoneal fluid. Two patients demonstrated a negative correlation. The submission of an inadequate amount of ovarian or appendiceal tissue for histologic examination may account for the discordance in three patients. It is concluded that pseudomyxoma peritonei is a distinct clinicopathologic entity which can be subdivided into two types, acellular and cellular. This distinction, unlike the specific cytomorphologic features, may have prognostic significance.