Cytology of secondary vulvar Paget's disease of urothelial origin: a case report.

BACKGROUND: Primary cutaneous Paget's disease of the vulva is an intraepithelial adenocarcinoma most likely arising from a cutaneous stem cell with sweat gland epithelial differentiation or can be of sweat gland origin. Primary vulvar Paget's disease, however, can be mimicked by an internal noncutaneous neoplasm htat has extended to secondarily involve the vulva. Most commonly, this is due to an anal or rectal adenocarcinoma or a urothelial carcinoma. These malignancies may be detected in a vaginal or vulvar cytologic smear.

CASE: An 81-year-old woman with a past history of urothelial carcinoma in situ of the bladder presented severalyears subsequent to treatment for bladder cancer with extensive vulvar and vaginal disease, clinically interpreted as primary vulvar Paget's disease involving the vagina. Vaginal cytology showed a high grade malignancy. The patient subsequently underwent radical (total deep) vulvectomy and vaginal excision. Subsequent investigation of her bladder showed recurrent urothelial carcinoma in situ with extensive spread to the vagina and vulva, simulating primary cutaneous vulvar Paget's disease.

CONCLUSION: It is important to recognize secondary vulvar Paget's disease, although uncommon, because of the difference in therapy for primary and secondary vulvar Paget's disease. Certain cytologic characteristics in a vaginal or vulvar smear in a patient with suspected vulvar Paget's disease may aid in distinguishing them.