Vulvar Extramammary Paget Disease Detected by Cytology for Cervical Cancer Screening: A Case Report and Literature Review

BACKGROUND Vulvar extramammary Paget disease (EMPD) with abnormal cervical cytology is extremely rare. We encountered a case of secondary EMPD derived from urothelial carcinoma diagnosed after cytological examination for cervical cancer screening. We diagnosed the case promptly owing to suspicion based on the patient's medical history and vulvar appearance. We report the case and present a review of published cases of EMPD with abnormal cervical cytology. CASE REPORT A 77-year-old Japanese woman visited a hospital because cervical cancer screening raised the suspicion of adenocarcinoma. Findings of the cytological examinations of the cervix, endometrium, and urethral meatus corresponded to those of other malignant neoplasms of the Bethesda system. The patient had undergone total urethral cystectomy for urothelial carcinoma 5 years earlier. In our hospital, we found erythema extending from the urethral meatus to the vulva and performed a vulvar biopsy based on the suspicion of recurrence of the urothelial carcinoma. We diagnosed secondary EMPD derived from the urothelial carcinoma based on the findings of Paget cells in the epithelium and immunohistochemistry. CONCLUSIONS A review of all the reported cases of EMPD with abnormal cervical cytology shows that the frequency of primary lesions is high in primary EMPD and secondary EMPD derived from urothelial carcinoma. These cases demonstrated the difficulty of suspecting EMPD based on cervical cytology alone. It should be considered that the cells derived from vulvar EMPD can be observed in cervical cytology, particularly in patients with a history of primary EMPD or urothelial carcinoma and with vulvar symptoms.