Extramammary Paget Disease

Key Points
Cancerous condition affecting the anogenital region
25% of cases are associated with another, underlying cancerous condition
Most cases occur in women of middle years
Consists of an itching lesion found in the groin or perianal area, which may be accompanied by pain or bleeding from scratching
May develop into thickened plaques, red in color which area scaly/crusty

Extramammary Paget Disease is a rare cancerous condition affecting the anogenital region. It initially consists of an itching lesion in the genital or perianal area, which over time may be experience pain and bleeding due to scratching of the area. Over time, thickened plaques may develop in the affected area, which are scaly, crusty, and red in color. In women, the most common area of involvement is the vulva, where burning, itching lesions may persist for a long period of time and spread to other areas of groin and periana area, even into the anal canal itself.

In roughly 1/4 of Extramammary Paget Disease cases, its appearance is related to another underlying cancerous condition, either in situ or invasive. In some cases, EPD may appear 10-15 years prior to signs of a related cancer or metastasization. The location of EPD lesions can be helpful in predicting associated cancerous conditions. Twenty-five to thirty-five percent of EPD lesions appearing in the perianal area were associated with underlying colorectal cancer. EPD is more common in women of middle years (50-60).

Differential Diagnosis (Other conditions with similar appearance)
Basal cell carcinoma
Intertrigo
Bowen Disease
Lichen Simplex Chronicus
Candidiasis, Cutaneous
Psoriasis, Plaque
Contact Dermatitis, Irritant
Tinea Cruris

Diagnosis
Key Points
Diagnosis based on appearance of the affected area
Skin biopsy will be performed to confirm diagnosis and rule out other, similar appearing conditions
Other tests may be necessary to distinguish it from other cancers, or to determine if an underlying condition exists

Extramammary Paget Disease is initially diagnosed based on the appearance of the affected area. A biopsy of the lesion will generally confirm diagnosis and rule out similar-appearing conditions. Other tests, such stain tests, may be necessary to distinguish it from other cancerous conditions, and to determine if an underlying cancerous condition exists.

Treatment
Treatment generally requires excision
Goal of treatment is to remove the lesion and watch closely for recurrence
*Immune response modifier therapy may assist in treatment

The best treatment for EPD is surgical excision, generally using Mohs microsurgery to ensure that detailed removal of the entire lesion to sufficient depth is achieved. Re-examination every three months is key, as recurrence is likely due to often unclear margins of the lesions. Additionally, immune response modifier therapy (Imiquimod cream) has been shown to be effective in combating the condition.