While endometriosis usually affects tissues in the pelvic region, in rare cases, atypical endometriotic tissue can infiltrate and grow in distant sites in the abdomen and chest.
A review shows that while the condition can be difficult to diagnose, the cyclic nature of symptoms — waxing and waning along with the menstrual cycle — may indicate the presence of atypical endometriosis.
Published in the journal RadioGraphics, the review was titled “Atypical Sites of Deeply Infiltrative Endometriosis: Clinical Characteristics and Imaging Findings.”
While endometriosis is common, lesions are typically found in the pelvic region, affecting tissues such as the vagina, ovaries, fallopian tubes, or the colon.
In about 8.9 percent of all cases, a deep infiltrating endometriotic lesion starts growing elsewhere. While the gastrointestinal and urinary tracts are most commonly affected by such atypical endometriosis, more than 60 percent are found elsewhere.
Endometriosis lesions have been found in the lungs, navel, liver, gallbladder, pancreas, pelvic nerves, groin, breasts, and extremities, as well as in abdominal scars, the research team from University of São Paulo and the women’s imaging center Chamié Imagem da Mulher said.
Lesions found in the abdominal wall — among the most common sites of atypical endometriosis — are strongly linked with surgical procedures.
There are several theories regarding how endometrial tissue can get to the sites — sometimes distant and not in direct contact with the pelvic organs.
Some believe that endometrial cells simply are transferred accidentally during a surgical procedure. Others think that stem cells lodge in these sites and turn into endometrial cells later. Endometrial cells also may travel in the lymph nodes to reach distant organs, some researchers claim.
As with other types of endometriosis, a quick diagnosis is rarely the case for atypical disease. Atypical locations may lead to even further delay in diagnosis compared to more common endometriosis sites, researchers said.
Some instances, however, may be easier. In many patients, associated pain often intensifies during menstruation, making it easier for physicians to diagnose the condition. For some sites, including the abdominal wall, the pain also is very localized.
Endometriosis in the lungs commonly gives rise to pain and typical signs — including the leakage of air or blood, or coughing of blood — during menstrual periods.
Imaging is of great help in diagnosing atypical endometriosis, the team said. Depending on the site, ultrasonography, magnetic resonance imaging (MRI), thin-section computed tomography (CT), as well as ordinary X-ray scans, may help physicians locate the lesion.
Nonetheless, physicians need to perform extensive examinations to make sure they have identified all lesions. Many women with atypical endometriosis may have lesions in more common locations, too.
As with other types of endometriosis, the review found surgery the best approach to definitive treatment. A thorough excision of all lesions may have good outcomes, but multidisciplinary teams often are needed, given the mix of organ systems involved in the condition.