Cytological features of a complete hydatidiform mole in a cervicovaginal smear: A case report

Exfoliated trophoblastic cells can be seen in a cervicovaginal smear in cases of normal pregnancy or gestational trophoblastic disease (GTD) and can mimic high-grade squamous intraepithelial lesion (HSIL) or malignancy. Although they appear highly anaplastic, cytological features such as high nuclear to cytoplasmic ratio, irregular nuclear contours and scanty basophilic cytoplasm admixed with cytologically benign squamoid and endocervical cells can aid in differentiating them from malignant cells. We present a case of a 37-year-old woman with abnormal uterine bleeding for 3-months. There was no history of recent pregnancy or previous GTD. Her cervicovaginal smear showed a hypercellular smear exhibiting cytologically benign superficial and intermediate squamous cells along with clusters of benign endocervical cells with interspersed mononucleate cells. These mononucleate cells were large, with a hyperchromatic, pleomorphic nuclei, and scant basophilic cytoplasm. Cytological features were suggestive of trophoblastic cells and workup for pregnancy and GTD was advised. Her laboratory investigations showed markedly raised levels of β human chorionic gonadotropins (β-HCG) and ultrasound showed a uterine mass with snowstorm appearance. A uterine evacuation was performed after which histopathological examination showed microscopic features consistent with a complete hydatidiform mole. The rare presence of trophoblastic cells in a cervicovaginal smear can easily be confused with malignant cells and can be misleading to the pathologist. Trophoblastic cells should always be kept in mind when evaluating a cytology smear of a young patient irrespective of gestational status.