Extramammary Paget disease (EMPD) is a rare neoplastic condition that represents 1% of vulvar cancers and usually occurs in the sixth to eighth decades of life. EMPD may be primary and arise as an adenocarcinoma, or it may be secondary due to spread of a neoplasm. Primary EMPD is thought to be a disorder of apocrine gland-bearing skin. Secondary EMPD may be due to extension of an adnexal adenocarcinoma or due to an underlying malignancy. EMPD may invade and metastasize via lymphatics. The most commonly associated visceral malignancies are anorectal and urothelial, but other associations include cervical, ovarian, and endometrial malignancies.

The condition is most often seen in elderly white women, except in Japan where there is a male preponderance.

Clinically, lesions most commonly appear in women on the vulva. Lesions are often banal in appearance and can resemble eczema, leading to delays in diagnosis. Symptoms may be minimal to none; often, there is itch, pain, or burning. Presentation is typically of a red, sharply demarcated plaque that expands slowly. Areas within the plaque are marked by erosions and white scale, leading to the appearance of "strawberries and cream." Approximately a quarter of vulvar EMPD is invasive, which portends a worse prognosis. Mortality has been shown to be higher in patients with vaginal EMPD than in those with vulvar / labial EMPD.

Approximately 10% of patients with a new diagnosis of EMPD are diagnosed with a noncontiguous associated malignancy within 12 months of diagnosis. An additional 10%-25% of patients have a contiguous malignancy at the time of diagnosis. The most commonly associated malignancies are cancers of the urinary tract, gastrointestinal tract, and vulva. Associated carcinomas of the cervix, vagina, endometrium, bladder, and Bartholin glands have also been described. The site involved predicts the site of secondary malignancy. For example, patients with anal, colorectal, or vulvar disease are at higher risk of malignancy in those areas. Due to these associations, a thorough investigation for underlying malignancy should accompany every diagnosis.

Surgery is the mainstay of treatment, but recurrence is common. Vulvar EMPD has a reported recurrence rate ranging from 12%-61%.