Endometriosis typically occurs in the ovaries and fallopian tubes. But it can develop anywhere in the body, including along or within the abdominal wall.

Endometriosis, broadly speaking, occurs when cells similar to those found in the uterine lining (endometrium) grow in other places of the body, says Heather Jeffcoat, DPT, author of ”Sex Without Pain: A Self-Treatment Guide To The Sex Life You Deserve.”

Abdominal wall endometriosis (AWE) is a rare form of endometriosis. It occurs when uterine-like cells grow along or within the abdominal wall.

Some people with AWE won’t have any symptoms at all, according to Jeffcoat.

When symptoms do occur, they typically include:

  • abdominal swelling, tenderness, or bruising
  • abdominal or pelvic pain, particularly during menstruation
  • a noticeable lump or mass in the abdomen

“Due to the scar tissue that can develop when you have abdominal wall endometriosis, many people also feel restrictions in movement with certain positions, such as trunk rotation or extension,” adds Jeffcoat.

Endometriosis is an idiopathic disease, which means it has no known cause — and that stands for AWE, too.

“The exact cause of abdominal wall endometriosis is unclear,” says Laura Purdy, MD, OB-GYN, chief medical officer at Wisp, a telehealth platform focused on sexual and reproductive health.

The disease seems to occur more frequently in people with a history of gynecological or obstetrical surgery.

Researchers in one small 2019 study analyzed medical records from an 11-year period to identify confirmed AWE diagnoses. Of the 35 women they identified, 29 had previous surgeries in the abdominal area — most commonly a cesarean section.

A slightly larger study published in 2022 found that 55 of the 83 women studied previously had a cesarean section.

“One theory suggests that during abdominal surgeries, endometrial tissue may get unintentionally implanted along the abdominal wall and result in abdominal wall endometriosis,” explains Purdy.

“[Another] theory of how abdominal wall endometriosis forms is the backward flow of menstrual blood through the fallopian tubes,” says Cheruba Prabakar, MD, OB-GYN, a fellowship-trained minimally invasive surgeon.

This is known as retrograde menstruation.

The idea is that drops of blood can implant at various places in the pelvis, including the side wall, bowel, rectum, ovaries, and abdominal wall, she says.

You’ll notice that the language used to share stats and other data points is pretty binary, fluctuating between the use of “male” and “female” or “men” and “women.”

Although we typically avoid language like this, specificity is key when reporting on research participants and clinical findings.

Unfortunately, the studies and surveys referenced in this article didn’t report data on, or include, participants who were transgender, nonbinary, gender nonconforming, genderqueer, agender, or genderless.

The gold standard for any endometriosis diagnosis is a laparoscopic surgical biopsy, says Jeffcoat.

Your clinician will take a sample of any growths, adhesions, or atypical tissues that endometriosis may have caused, then send it to a lab for testing.

Although experts consider a laparoscopic biopsy a minimally invasive procedure, it’s still surgery.

There’s been a push in recent years for clinicians to diagnose AWE with the help of symptom logging and imaging technologies, including ultrasounds, MRIs, and CT scans.

This could spare folks the time and expense associated with surgery and allow for a more rapid turnaround in results.

There’s currently no cure for endometriosis, but it’s treatable through surgical, holistic, and lifestyle interventions.

Full excision surgery is usually the most effective way to reduce pain associated with the disease. This involves cutting out the affected tissues and a recommended margin of one centimeter surrounding the affected area.

“But while excision surgery is a critical intervention, pain is complex, and at the point where the pain has become chronic, there’s rarely a single intervention that reverses an individual’s pain,” notes Jeffcoat.

An effective treatment plan might also include working with a pelvic floor therapist, acupuncturist, chronic pain specialist, and nutritionist, she says.

“Treatment may also include medications such as hormonal contraceptives and nonsteroidal anti-inflammatory medication,” adds Purdy.

AWE can cause painful menstruation, says Purdy.

Endometrial cells act similarly to the cells lining the uterus, which means that they can thicken, break down, and shed.

Unlike the uterine lining, which can leave the body through the vaginal canal, the endometrial cells along the abdominal wall have nowhere to go. As a result, these cells get trapped and cause painful adhesions.

“Skin changes such as discoloration or hyperpigmentation in the abdominal wall are another possible complication,” she says.

A 2022 case report suggested that 30–50% of people with endometriosis — namely pelvic endometriosis — experience infertility.

Although AWE often occurs with pelvic endometriosis, having one doesn’t necessarily indicate the presence of the other.

Experts need more research to determine whether AWE alone can affect fertility.

“While abdominal wall endometriosis can pose challenges, with appropriate care and support, individuals can find relief and continue to enjoy a fulfilling life,” says Purdy.

So, if any of the above symptoms seem familiar, talk with a healthcare professional.

Better yet, talk with one who specializes in endometriosis care. Use The American End of Endo Project Provider Directory or iCare Better expert search to find one near you.

AWE is a rare disease that occurs when uterine-like tissue grows inside or along the abdominal wall. Experts usually see it in people with a history of gynecological or obstetrical surgery, especially cesarean section.

Many people with AWE don’t experience symptoms, while others report pain and cramping. If you suspect that your symptoms may be related to AWE or another form of endometriosis, talk with a healthcare professional.

Gabrielle Kassel (she/her) is a queer sex educator and wellness journalist who is committed to helping people feel the best they can in their bodies. In addition to Healthline, her work has appeared in publications such as Shape, Cosmopolitan, Well+Good, Health, Self, Women’s Health, Greatist, and more! In her free time, Gabrielle can be found coaching CrossFit, reviewing pleasure products, hiking with her border collie, or recording episodes of the podcast she co-hosts called Bad In Bed. Follow her on Instagram @Gabriellekassel.