Extramammary Paget disease (EMPD) is a very rare form of skin cancer, affecting an estimated one in a million people in the U.S. It tends to grow slowly, but if left untreated, it can become invasive and spread to other parts of the body. That’s why early detection is so important.
Because it’s so rare, many doctors may never see a case in their careers. To help us understand more, we spoke with Phyu Aung, M.D., Ph.D., a dermatopathologist who specializes in rare skin cancers like EMPD.
What is extramammary Paget disease?
EMPD is similar at the cellular level to a cancer called Paget’s disease of the breast. When it appears outside the breast — on areas like the genitals, anus or armpits — it’s called extramammary, meaning “outside the breast.”
What are the symptoms of extramammary Paget disease?
EMPD can look like many common skin conditions. It often appears as a red, scaly or irritated patch of skin. It may itch or hurt — or it may not cause any discomfort at all. Because of this, it’s often mistaken for things like eczema, psoriasis or a fungal infection. Some people go months or even years before getting the correct diagnosis.
If a skin condition doesn’t improve with standard treatments, it’s worth asking your doctor to take a closer look.
Where does extramammary Paget disease usually appear?
Extramammary Paget disease typically shows up in areas with many sweat glands, such as:
Women: Most commonly the vulva
Men: Scrotum and penis
Both: Around the anus, perineum or armpits
Are there different types of extramammary Paget disease?
Yes. There are two types of extramammary Paget disease:
Primary EMPD starts in the skin or mucous membranes and stays there.
Secondary EMPD is linked to internal cancers, such as rectal, bladder or prostate cancer in men, and cervical, ovarian or endometrial cancer in women.
About one-third of EMPD cases are secondary, so doctors will usually screen for internal cancers when EMPD is diagnosed.
How is Extramammary Paget disease diagnosed?
If a doctor suspects EMPD, they’ll usually perform a biopsy, removing a small piece of skin to examine under a microscope. Because EMPD can resemble other skin cancers, special tests (called immunohistochemical stains) are often used to confirm the diagnosis and check for any deeper spread.
If EMPD is confirmed, additional tests may be needed to see if it has spread or if there’s an internal cancer involved.
How is extramammary Paget disease treated?
Treatment depends on how far the disease has progressed:
When Extramammary Paget disease is limited to the skin (called intraepidermal EMPD):
Surgery is often the first choice, especially if the goal is to remove all cancer cells. A technique called margin-controlled surgery helps ensure all affected tissue is removed.
If surgery isn’t possible or would cause too much harm, topical treatments like imiquimod cream may be used before or after surgery.
EMPD often comes back, so regular follow-up visits are important.
When EMPD has spread deeper (called invasive EMPD):
Surgery is still the main treatment, often with wider removal of tissue.
If cancer cells are found at the edges of the removed area and more surgery isn’t an option, radiation therapy or topical treatments may be added.
Radiation can also be used if surgery isn’t possible or if the cancer returns.
When EMPD has spread to other parts of the body (called metastatic EMPD):
Treatment may include chemotherapy, targeted therapy or immunotherapy.
A team of specialists (called a tumor board) usually works together to create the best treatment plan.
What should newly diagnosed patients know?
Although EMPD is rare, you’re not alone. It’s important to seek care at a specialized cancer center like MD Anderson, where doctors have experience with this condition and can offer a personalized, team-based approach to treatment.