Characterising umbilical abdominal wall endometriosis as a distinct subgroup of abdominal wall endometriosis - retrospective cohort study.

Abdominal wall endometriosis (AWE) is one of the rarest forms of endometriosis. Little is known about differences between umbilical AWE (U-AWE) and non-umbilical AWE (non-U-AWE) patients. This retrospective cohort study included patients treated for AWE at tertiary endometriosis centre between 2012 and 2020. Patients were divided into two groups - umbilical AWE and non-umbilical AWE.We identified 14 U-AWE and 45 non-U-AWE patients who mostly had lesions in caesarean section scar (38, 64.4%), rarely at other locations (7, 11.9%). Infertility rates for U-AWE patients and non-U-AWE patients were 57.1% and 17.8%, respectively. Concurrent or previous peritoneal endometriosis was noted in 85.7% of U-AWE and 24.4% of non-U- AWE patients. In addition, U-AWE patients and non-UAWE patients significantly differed in following: parity, number of previous caesarean sections, lesion size, prevalence of concurrent or previous deep infiltrating endometriosis, bleeding from abdominal wall, cyclic pain, continuous pain.Infertility and pelvic endometriosis were more prevalent in U-AWE patients. Our data suggests that U-AWE may be a specific marker for a patient highly prone to pelvic endometriosis and subsequent infertility. Findings suggests that clinician should consider comprehensive evaluation of U-AWE patients.