Vulvar or extramammary Paget's disease is an adenocarcinoma of the vulva that is usually confined to the squamous epithelium (intraepithelial), but which may become invasive. It usually occurs in postmenopausal females, and often gives pruritic or painful symptoms, which may be incorrectly treated as dermatitis
The gross appearance is red pink, or eczematous, and involvement may be extensive and may involve the anus. Microscopically, there are malignant glandular cells within the squamous epithelium (intraepithelial), sometimes in underlying dermis.
The two main types may be of primary vulvar skin origin or metastatic origin (primarily from the colon, rectum, cervix, other non-skin sites). Diagnosis occurs with incisional or excisional biopsy and microscopic examination. The majority of primary intraepithelial lesions are slowly progressive and superficial, though there is a less favourable prognosis if the the tumour is primary, invasive or metastatic.