Over recent months I have seen an unusual number of patients with endometriosis in various scar sites. The most common situation follows the performance of a caesarian section with a deposit of endometriosis within the operative field. More rarely and usually without prior surgery (including laparoscopy) the umbilicus can be affected. Interestingly I have not seen any endometriotic deposits within trocar sites.
The most common presentation is of a nodule of endometriosis somewhere within a caesarian scar. Most caesarian section scars are Pfannenstiel or bikini type scars across the lower abdomen. Although the skin incision is horizontal the underlying incision through the rectus sheath or covering fascia over the abdominal musculature is vertical and it is in this area that the nodule will develop. As a consequence the nodule may not overly the actual skin incision and may be situated anywhere along this line or extended up and towards the umbilicus. These nodules usually cyclically swell and become painful and most patients take some time to appreciate the significance of what is occurring. They are usually imaged with ultrasound and fine needle aspiration biopsy will reveal the diagnosis. The endometriosis in this area presumably has arisen as a result of the deposition of endometrial tissue at the time of the caesarian embedded within the scar. The endometriosis behaves in this area in a similar fashion to endometriosis in other sites and tends to develop a cicatrizing or scarring type effect. It can be likened somewhat to the example of a table cloth which if it could be grasped by one hand in the middle and a small area pulled into a ball, if that area is then cut out the resulting defect can be quite large. Many of the patients I have seen have had incomplete excision of the nodular area with subsequent recurrence. The nodules usually involve a portion of the rectus sheath although occasionally they can be above or below the rectus sheath. If the rectus sheath is involved and a large area is removed the resulting defect will require primary closure and if it is significantly large it may not be possible to achieve this. In that setting some form of mesh repair similar to a hernia repair will be required otherwise a hernia will develop. Caesarian scar endometriosis is often an isolated finding and at laparoscopic investigation further endometriosis may not be encountered within the pelvis.
Umbilical endometriosis by contrast is usually associated with pelvic endometriosis and is dealt with in a similar fashion. Other areas of involvement include the cervix and episiotomy scars. The cervical disease usually follows a surgical procedure to deal with abnormal pap smears.