Challenges in the Interpretation Peritoneal Cytologic Specimens (Report‪)‬

Peritoneal washing cytology has been used in the evaluation of gynecologic malignancies since the early 1950s. The International Federation of Gynecology and Obstetrics (FIGO) introduced peritoneal washing as part of the staging of ovarian carcinomas in 1975. For ovarian carcinomas, the presence of malignant cells in peritoneal washings is important for substaging patients with disease that is apparently organ-confined (FIGO stage I) and for the detection of recurrent carcinoma. Tumor confined to an ovary is considered FIGO stage IA, whereas ovarian carcinomas involving the ovarian surface and/or detectable in a peritoneal washing specimen is assigned FIGO stage IC. A 5-year survival rate of 90% in patients with stage IA, grade I ovarian carcinomas contrasts with 68% and 56% in patients with stage I lesions showing ovarian excrescences or ovarian capsular rupture, respectively. Similar results were found in second-look laparotomy patients. (1) Survivals in patients with ovarian carcinoma have also been reported to differ significantly, based on peritoneal cytology, regardless of disease stage. The progression-free interval and survival rate are reportedly influenced significantly by tumor grade and the presence of microscopic tumor identified on the basis of biopsy or cytology. (2-6) The presence of malignant cells in peritoneal washings from patients with endometrial carcinoma assigns the tumor to FIGO stage IIIA or higher. Most studies suggest that cytology is a predictor of poor outcome, (3, 7, 8) but the clinical significance of positive peritoneal washings in patients with non-myometrial invasive, FIGO grade I endometrioid adenocarcinoma is debatable. (8) The presence of malignant cells in washings is also an independent, negative prognostic factor in patients with advanced-stage disease. These patients have a reported recurrence rate of 23%, which is similar to that of patients with occult lymph node metastasis identified through surgical staging. Currently, patients with cytologically defined stage IIIA endometrial cancer are included among patients with advanced-stage disease, (9) but this may be reassessed in an upcoming revision of the guidelines for FIGO staging of endometrial carcinoma.