Cytohistologic correlation of peritoneal washing cytology in gynecologic disease

The peritoneal washings and cul de sac aspirates from 204 patients undergoing 217 procedures for the evaluation of gynecologic disease were examined retrospectively and correlated with the histologic diagnoses. Of the 73 washings from patients with histologically benign genital disease, cytology diagnosed 64 (87.7%) as negative, 6 (8.2%) as inconclusive and 3 as malignant. One malignant washing was a true positive from a nongenital primary. False positives thus occurred in 2.7% of the benign cases on blind review. Of 144 cytologic examinations of washings from patients with histologically confirmed malignant disease of the female genital tract, 38 (26.4%) were considered positive after cytohistologic correlation. Four malignant cases (2.1%) were undercalled on blind review while 3 (2.0%) were considered overcalls. Eleven of 47 cases (23.4%) with biopsy-proven peritoneal disease had negative cytology after histologic correlation. Recurring problems in interpreting peritoneal washings included: (1) the differential diagnosis of the spectrum encompassed by reactive mesothelium, endosalpingiosis, borderline serous tumors and well-differentiated serous cystadenocarcinoma; (2) morphologic similarities between some tumor cells and mesothelial cells associated with treatment effects; and (3) a paucity of malignant cells in some washings, resulting in false-negative interpretations. Ineffective cytopreparation, particularly of bloody specimens, hampered interpretation of some specimens. Correlation with previous histology and cytology enhanced the accuracy of peritoneal washing cytology in this study.