Basal cell carcinoma within vulvar Paget's disease.

An 85-year-old Japanese woman had noticed erythema on her vulvar region 3 years before. The erythema gradually increased in size and followed erosion and ulceration with pigmentation on the edge of the erythema. A skin biopsy from the pigmented area showed large round cells with ample cytoplasm, which formed nests or glandular structures. In the dermis there was mass formation of basophilic cells and peripheral cells in a palisade arrangement. The tumor cells in the epidermis showed positive immunoreactivity for carcinoembryonic antigen; on the other hand, the dermal tumor was negative. We diagnosed that the tumor in the epidermis was vulvar Paget's disease, and the dermal tumor was a solid type of basal cell carcinoma. We speculate that the vulvar Paget's disease preceded and then the basal cell carcinoma developed in the area of Paget's disease. This is the first report in which basal cell carcinoma in the area of Paget's disease was documented.