Pigmented extramammary Paget's disease of the axilla mimicking melanoma: case report and review of the literature.

Pigmented Paget's disease is a rare variant that is often confused clinically and histologically with melanoma in situ. Herein, we describe a case of pigmented extramammary Paget's disease involving the axilla of a 79-year-old white male thought initially to represent malignant melanoma clinically and histologically. Review of the literature reveals that pigmented variant of Paget's disease, either mammary or extramammary, could be initially misdiagnosed as melanoma unless this entity is considered in the differential diagnosis, and additional confirmatory studies are performed.