Diagnostic Dilemmas

Peritoneal washing cytology is important in the staging, prognosis, and treatment schema for women diagnosed with gynecologic malignancies. Additionally, peritoneal washings are often performed before the specific diagnosis or even the distinction between benign or malignant lesion is known. Occasionally, the cytology and surgical pathology specimens, although obtained during the same procedure, will show unexpected and/or discordant findings. Perhaps, the greatest dilemma occurs when atypical cells suggestive of malignancy are identified in peritoneal washing specimens when a corresponding benign or discordantly low grade malignant diagnosis is made in the surgical pathology specimen. We present two such cases in which further investigation proved extremely valuable, not only leading to resolution of initially discrepant cytologic and surgical pathology findings but also in the process leading to second diagnoses of early fallopian tube carcinoma. Increasing evidence appears to be pointing to the fallopian tube as the site of origin of many serous carcinomas previously thought to be of primary pelvic or ovarian origin. These cases further confirm the utility of peritoneal washing cytology as a diagnostic modality when routine gross examination and sampling of the surgical specimens alone would have failed to provide the complete diagnosis. Diagn. Cytopathol. 2009;37:923–929. ' 2009 Wiley-Liss, Inc.