Getting under your skin

Endometriosis can be found pretty much anywhere in the body (I’m going to do a separate post on that at some point, but I digress) for this post though I’ll be focussing on endometriosis of the skin, or cutaneous endometriosis as it is known. There have been several reports of endometriosis found on the skin, although the phenomenon is still considered rare, reports of this subtype of endometriosis go back to the 50’s. Most commonly cutaneous endometriosis is found on surgical scars and around the umbilicus (belly button/navel). Symptoms typically include cyclic pain emanating from a mass near/on a scar or the umbilicus and can be misdiagnosed as suture granuloma, lipoma, abscess, cyst, hernia or skin cancer.

Let’s take a look at reports of some typical examples; three years after having a caesarean section a 37 year old woman found a nodule under her scar that became painful during menses. The nodule was removed surgically and after examination it was found to be cutaneous endometriosis. Another report found a woman with dark brown mass on the umbilicus associated with cyclic pain. Although the woman was found not to have pelvic endometriosis the mass on her umbilicus was found to be endometriosis.

The reason for me discussing cutaneous endometriosis is that a paper has recently been published in Brazil that suggests caesarean section greatly increases the risk of endometriosis developing on the scar. The study looked at 72 patients diagnosed with scar endometriosis between 1978 and 2003. It was found that the risk of scar endometriosis developing was far higher after caesarean section, where the risk was 0.2%, than other procedures e.g. episiotomy, where the risk was 0.06%. There are several parallels that can be drawn between cutaneous endometriosis and pelvic endometriosis. Both conditions are often misdiagnosed, both present with cyclic pain and we still don’t really understand how the disease gets to where it is. As cutaneous endometriosis appears around scars it could be hypothesised that somehow fragments of endometrium find their way into the open wound during surgery where they later form endometriotic implants.

The good news though is cutaneous endometriosis can be easily removed with surgery and once it is gone it usually doesn’t come back.