Pseudomyxoma peritonei (PP) is a rare condition. Cytologic evaluation of peritoneal fluid often is an initial diagnostic test for possible ovarian and/or appendiceal primary tumors. Previous studies suggest that patients with PP who have epithelial cells (ECs) in their peritoneal fluid usually have a less favorable prognosis than patients with acellular PP. To the authors' knowledge, few reports of PP in the cytologic literature cite the presence of ECs.
Twelve cases of PP diagnosed by cytologic examination at the University of Texas M. D. Anderson Cancer Center over 15 years were identified. In all cases, primary tumors were confirmed histologically. All available cytologic smears and cell block sections were reviewed for cytomorphology, with particular attention given to the presence of ECs. A correlation between the presence of ECs and patient outcome also was sought (median follow-up, 26 months).
Two patients had ovarian neoplasms, six patients (one female and five males) had appendiceal neoplasms, and four patients had synchronous ovarian and appendiceal tumors. Cytologic features included mucin pools (12 of 12 patients), ECs (11 of 12 patients), mesothelial or mesothelial-like cells (10 of 12 patients), histiocytes (11 of 12 patients), and fibroblast-like or spindle cells (6 of 12 patients). ECs were columnar with mucinous features in the majority of cases, and the number of ECs in each case was variable, ranging from 1+ (rare) to 3+ (many). Of the 11 patients with available follow-up data, 6 had recurrent disease, 4 had persistent disease, and 1 patient with acellular PP was alive without clinical evidence of disease after 24 months of follow-up.
Unlike previous PP cytology reports, the current study frequently identified ECs (92%). Because of the potential prognostic implication of ECs in patients with PP, a diligent search for ECs is warranted. Indication of the presence or absence of ECs in the cytology report may be useful when PP is diagnosed.