Catch Me If You Can! Keeping an Eye Out to Detect Unusual Malignancies Appearing in Cervical Pap Smear.

Abstract

Background: Metastatic involvement of the uterine cervix by extrauterine non-gynecological malignancies is exceptionally rare due to the cervix's unique lymphatic and vascular characteristics. Detection of such unusual malignancies in cervical Papanicolaou (Pap) smears poses significant diagnostic challenges but can offer critical early clues.

Objective: This study aimed to evaluate the spectrum and cytomorphological features of extrauterine nongynecological malignancies involving the cervix detected incidentally on routine cervical Pap smears.

Materials and methods: A retrospective analysis was conducted on 12,980 cervical Pap smears screened between January 2019 and December 2024 in a tertiary care center. Twenty-seven cases of extrauterine nongynecological malignancies were identified. Cytological findings were correlated with clinical, radiological, histopathological, and immunohistochemical data.

Results: The mean patient age was 54 years (range: 22-84). The most common metastatic sites were the lower gastrointestinal tract (33.3%), breast (14.8%), vagina (22.2%), and other sites, including gallbladder, urinary bladder, retroperitoneum, and hematologic malignancies. In 33.3% of cases, the Pap smear provided the first diagnostic clue for an unknown malignancy. Cytological features varied across primary sites: gastrointestinal metastases showed tall columnar cells and signet-ring morphology; breast carcinoma displayed poorly differentiated cells; and melanomas exhibited pigmented cells with prominent nucleoli. Rare diagnoses included metastatic urothelial carcinoma, anaplastic large cell lymphoma, and retroperitoneal leiomyosarcoma.

Conclusion: Although rare, extrauterine malignancies can be detected on cervical Pap smears and may even present as the first sign of disease. Awareness of subtle cytomorphological patterns, combined with clinical correlation and immunohistochemical studies, is essential to avoid misinterpretation and ensure accurate diagnosis and timely management.