What is Cutaneous Endometriosis?
Endometriosis is a condition that affects women of reproductive age. It is characterized by tissue similar to the lining of the uterus (called endometrial glands or stroma) being found outside the uterus. Commonly, endometriosis affects locations like the ovaries, the ligaments supporting the uterus, the area around the ovaries, the space behind the uterus, and the bladder.
Depending on the location of the tissue, endometriosis can be categorized as either inside the pelvis (endopelvic) or outside the pelvis or reproductive organs (extrapelvic/extragenital).
One particular type of extrapelvic endometriosis occurs on the skin, this is referred to as cutaneous endometriosis. This type is not very common and occurs when the endometrial tissue, which is not cancerous, appears on the skin. Patients with this condition often experience pain that aligns with their menstrual cycle, noticeable lumps, swelling, or even bleeding at the affected skin sites. If endometriosis occurs in surgical scars, it’s often called scar endometriosis, and this can be either on or under the skin, depending on where the lesions are found.
What Causes Cutaneous Endometriosis?
Endometriosis that affects the skin can be split into two types: primary cutaneous endometriosis and secondary cutaneous endometriosis. The cause of primary cutaneous endometriosis isn’t definitely known and it tends to occur on its own. On the other hand, secondary cutaneous endometriosis is thought to occur following abdominal or pelvic surgeries. This can happen when endometrial tissue, which normally lines the inside of the uterus, accidentally gets implanted into the skin during these surgical procedures.
Risk Factors and Frequency for Cutaneous Endometriosis
Endometriosis is a condition that affects between 5 and 15% of women who are able to have children. It can also show up on the skin, but this is less common, affecting around 0.5 to 1% of people. Primary cutaneous endometriosis, a specific type found on the skin, is even less common, making up less than 30% of all skin-based cases. About 30 to 40% of these skin cases are umbilical endometriosis, meaning they occur near the belly button. There’s also a very rare form of endometriosis that can happen in the scar from a birth injury, occurring in about 0.00007% of births, but this is likely underreported.
- Endometriosis affects 5 to 15% of women who can have children.
- Cutaneous endometriosis, or endometriosis on the skin, affects around 0.5 to 1% of people.
- Primary cutaneous endometriosis accounts for less than 30% of all skin-based cases.
- Umbilical endometriosis, which occurs near the belly button, represents 30 to 40% of skin-based cases.
- Endometriosis in an episiotomy scar, a scar from a birth injury, occurs in about 0.00007% of births, though this is likely underreported.
Signs and Symptoms of Cutaneous Endometriosis
Cutaneous endometriosis is a condition that mostly affects females of reproductive age, but it can also occur in adolescents. Often, this condition develops in those who have had surgical procedures like cesarean sections, laparoscopies, tubal ligations, hysterectomies, or episiotomies. These previous operations could lead to endometrial tissue – the tissue that lines the womb – embedding itself into the surgical scar.
The usual symptoms associated with this condition include a cyclical pain that aligns with the menstrual cycle, swelling that intensifies during menstruation, a noticeable lump, or bleeding from the skin in affected areas.
Typically, people with cutaneous endometriosis will have a firm bump or lump that measures around 2 cm across. If there’s a lump in the belly button area that causes pain, itching, bleeding, or discharge, it might be an indication of umbilical endometriosis. The affected areas often show signs of inflammation, such as redness.
If you encounter these signs and symptoms, especially near previous surgical scars or the extremities, it could suggest cutaneous endometriosis. Usually, the symptoms appear an average of 4.2 years after a relevant surgical procedure.
Testing for Cutaneous Endometriosis
If your doctor suspects that you have skin endometriosis, they may start by examining your medical history, especially any past surgical procedures. This information could help them identify whether the condition is primary or secondary.
To confirm skin endometriosis, a biopsy of the suspected area is typically performed. This involves taking a small sample of skin tissue and examining it under a microscope for signs of endometriosis. However, a technique called fine-needle aspiration, which involves extracting tissue using a thin needle, is a matter of debate because it may spread the endometriosis to new areas and worsen the condition.
Instead, surgical excision is often favored. This means removing the suspicious skin tissue, leaving a safety perimeter of at least 1 cm around it. This method serves two purposes: it can confirm the diagnosis of skin endometriosis and treat it by removing the affected tissue entirely.
Imaging studies such as CT scans and MRI can be useful if your doctor suspects that a tumor might have spread to the skin from another part of the body, like the gastrointestinal tract. An example of this is ‘Sister Mary Joseph’s nodule’, which is a potential diagnosis alongside umbilical endometrioma, a type of skin endometriosis.
In some cases, a second biopsy may be necessary. This could be the case if a patient was previously treated with steroids for a suspected skin scar, known as a keloid, and didn’t respond to the treatment.
Lastly, if you are diagnosed with skin endometriosis, your doctor might recommend a gynecological examination. This is because studies have shown that about 14% of patients with endometriosis skin scars also have pelvic endometriosis.
Treatment Options for Cutaneous Endometriosis
The treatment for skin endometriosis can be hormonal or surgical, with pain relief being another component of care. Nonsteroidal anti-inflammatory drugs (NSAIDs) can be used to manage pain. Hormonal treatment options can include therapies that release hormones controlling the reproductive cycle, danazol, and birth control pills. These hormones help shrink endometrial tissues by reducing their growth.
Hormonal treatments are often used to shrink lesions and alleviate symptoms before surgery. However, patients should be fully informed of the potential side effects before beginning these treatments. Side effects can include the absence of periods with danazol and leuprolide, and the condition may return once hormonal treatment is stopped. Danazol can also cause acne, weight gain, unusual hair growth, and a deepened voice. This treatment can be an alternative for those who do not want surgery or have endometriosis elsewhere in the pelvis. Even so, the best treatment is usually surgery to remove the lesion completely.
Reoccurrence is rare after a surgery that successfully removes the entire lesion. However, when the surgery doesn’t manage to remove the whole lesion, the condition can return. There are differing opinions on the best time for surgery. Some suggest surgery should occur at the end of a patient’s menstrual cycle when the lesions are smallest. Others suggest using hormonal treatments before surgery to shrink the lesions. After surgery, hormonal treatments can also be used to prevent the condition from coming back. Combining hormonal therapy with surgery often results in the best outcomes for many patients.
What else can Cutaneous Endometriosis be?
Cutaneous endometriosis, a skin-related issue, can sometimes be confused with other conditions like keloid (scar-like tissue), dermatofibroma (noncancerous skin bumps), dermatofibrosarcoma protuberans (a rare type of skin cancer), cutaneous metastasis of cancer (cancer that has spread to the skin), or even melanoma (a dangerous type of skin cancer).
One key feature to watch for in suspecting cutaneous endometriosis is that it behaves in a cyclical manner. This means its symptoms might only appear at certain times, or it may cause a lump to grow and shrink in relation to a woman’s menstrual cycle. In other words, the discomfort or the size of the lump may increase and decrease following the start and end of monthly periods.
What to expect with Cutaneous Endometriosis
Generally, the outlook for patients with skin-related endometriosis is good. Recurrence is rare if the patient has undergone surgery to remove the endometriosis patches. According to a research study by Lopez-Soto et al. (2018), only 3 out of 33 women who had a treatment for cutaneous endometriosis experienced a recurrence, which is as low as 9%.
Possible Complications When Diagnosed with Cutaneous Endometriosis
Endometriosis is typically a benign (non-cancerous) condition, but there have been cases where it has turned into a malignant (cancerous) state. The exact number of instances where this happens isn’t well-known. Additionally, why endometriosis sometimes becomes malignant is also unclear. However, there are studies suggesting that genetic, immunologic (related to the immune system), and hormonal factors might play a part.
One complication worth noting is that endometriosis that develops in a cesarean scar can also become malignant. When it does, this typically results in more aggressive types of cancer known as endometrioid or clear cell carcinoma. Moreover, there’s also a possibility of endometriosis recurring after treatment which is another complication.
Preventing Cutaneous Endometriosis
There’s no way to prevent skin endometriosis. It’s important to carefully examine any skin growth, particularly if it appears at a previous C-section scar. Sometimes, these growths can be mistaken for a tumor by patients. To address this, doctors can provide a proper diagnosis and reassure the patient that the growth is treatable and not as serious as a tumor.
