Surgical exploration of primary umbilical and inguinal canal endometriosis: a cutaneous conundrum

Primary cutaneous endometriosis and inguinal endometriosis (IEM) are rare, representing less than 1% and under 0.6% of extragenital and extrapelvic endometriosis, respectively. Co-occurrence in the same patient is exceedingly rare, with a frequency as low as 5 cases per 100 000. This case presents the first instance of a patient simultaneously afflicted with both types. Endometriosis involves the ectopic presence of endometrial tissue, with primary umbilical endometriosis (PUE) localised in the umbilicus without prior surgery, and IEM affecting the inguinal canal. In a nulliparous woman in her early 30s, lacking surgical history, the diagnosis of PUE, IEM and pelvic endometriosis was made following presentation with chronic pelvic pain and a painful umbilical nodule. This report aims to delineate the presentation, diagnosis and surgical management of patients with umbilical and IEM, shedding light on these rare manifestations.