Extramammary Paget disease (EMPD) is characterized by a chronic eczema-like rash of the skin around the genital regions of males and females. Under the microscope, this condition looks very similar to a condition that occurs on the breast called mammary Paget disease. The primary difference between the two is the location of the rash. While the location of the rash for individuals with mammary Paget disease is around the nipple and areolar skin, EMPD may occur in the vulva, perianal region, scrotum, penis, and axilla. EMPD most often occurs in women between age 50 to 60. About 25 percent of extramammary Paget disease is associated with an underlying cancer. Treatment typically includes surgery. Prognosis varies depending on how early the disorder was diagnosed and treated as well as the association with an underlying cancer.

The cause of extramammary Paget disease (EMPD) remains unknown. Approximately 25% of cases are associated with an underlying tumor. The type of tumor that is most likely to be associated with this disease is an apocrine carcinoma. Other associated cancers include cutaneous adnexal carcinoma and carcinoma of the Bartholin glands, urethra, bladder, vagina, cervix, endometrium, or prostate. About 4-7% of patients with genital disease have an associated carcinoma. Perianal disease is associated with underlying colorectal cancer in 25-35% of cases.

The most common symptom of extramammary Paget disease (EMPD) is mild to intense itching of a lesion found around the genital or anal area. Pain and bleeding may result from scratching the lesions. The lesions can become thick, red, scaly, and crusty. In women, the most common affected area is the vulva. The location of extramammary Paget disease is useful in predicting the risk of associated cancer. Approximately 25-35% of EMPD around the anal region is associated with an underlying colorectal cancer.

Extramammary Paget disease (EMPD) is usually treated by surgically removing the skin lesion. It is sometimes difficult to determine how much skin should be removed, particularly when lesions are spread throughout the anogenital region. Because recurrence is common, it is standard for patients to be re-examined every 3 months after surgery for the next 2 years. After 2 years, annual follow-ups are usually recommended.

In cases where surgery is not a possibility due to recurrence or location; treatment options reported in the medical literature with varying levels of success include: chemotherapeutic agents such as 5-fluorouracil, imiquimod, paclitaxel, trastuzumab, and docetaxel as well as aminolevulinic acid photodynamic therapy, laser ablation, and radiation therapy. Unfortunately, studies regarding the effectiveness of the above treatment options are limited to mainly case studies and small literature reviews with limited follow-up.

Promising studies published recently include a study completed in Japan that reviewed the use of docetaxal as a first-line treatment in 13 individuals with EMPD with metastasis. 12 individuals were found to have a response to treatment with a disease control rate estimated to be 83%. Another promising study reviewed the use of imiquimod in 10 cases of EMPD of the vulva. Complete clinical remission was reported in 9 individuals. The remaining individual had partial remission.

There is an ongoing research study focused on evaluating the effectiveness of imiquimod in the treatment of EMPD. To learn more about this trial, please click on the following link through ClinicalTrials.gov
https://clinicaltrials.gov/ct2/results?term=extramammary+paget%27s+disease&recr

The prognosis for extramammary Paget disease (EMPD) depends on early diagnosis and surgical treatment. The prognosis is good for cases where the disease only affects the epidermal (top) layer of skin and the areas around the surgically removed lesion (margins) remain free of the disease. One study showed a mortality rate of 18% for patients without associated carcinoma and 46% for those with underlying carcinoma. Perianal disease, invasion into the dermal skin layer, and spread of cancer to lymph nodes are more likely to be associated with a poor prognosis. The rate of recurrence is approximately 30%. In those people who experience a recurrence of extramammary Paget disease, the average time it takes for the disease to recur is 2.5 years.

The diagnostic process for extramammary Paget disease (EMPD) should begin with a detailed review of systems and physical examination. Initial examinations could additionally include: full skin examination, palpation of all lymph nodes, rectal examination, sigmoidoscopy, cystoscopy.

When EMPD is suspected, the diagnosis is typically confirmed via skin biopsy of the lesion. Under the microscope, the presence of Paget cells along with other specific findings confirms the diagnosis. Special stains may be necessary to distinguish EMPD from early melanoma (melanoma in situ).