Researchers at NHS Greater Glasgow and Clyde in the United Kingdom have reported a rare case of spontaneous umbilical endometriosis in an asymptomatic patient. The study was published in the International Journal of Surgery Case Reports and is entitled “An unusual case of asymptomatic spontaneous umbilical endometriosis treated with skin-sparing excision”.

Endometriosis is a gynecological disorder in which the tissue that normally lines the inside of the uterus (called endometrium) grows outside the uterus, usually in the abdominal cavity, where it can form lesions and cysts, scarring organs like the ovaries, bladder and rectum. The tissue, although displaced, still continues to act normally as inside the uterus, so it thickens, breaks down and bleeds with each menstrual cycle. Endometriosis can be a painful disorder, causing inflammation and very heavy periods. It is estimated that 5 to 10% of women in reproductive age suffer from this condition and it can cause infertility in up to 50% of the women. The exact causes of this disorder are unknown.

One rare extrapelvic manifestation of this condition is spontaneous umbilical endometriosis, a disorder characterized by a wide variety of symptoms associated with umbilical lesions, usually synchronized with menstruation.

The study presents a case report of a 39-year-old female patient with a nodular lesion arising from her umbilicus adjacent to a previous long-standing peri-umbilical piercing site. The lesion had been present for 18 months and was completely asymptomatic, with no bleeding episodes or cyclical alterations during menstruation. At the time, different diagnosis were suggested including fibroma (tumor in the fibrous connective tissue) and keloid scarring (scar with overgrowth of collagen tissue).

Ultrasound scan of the lesion showed a superficial soft tissue nodule and the patient was submitted to skin-sparing excision in order to remove it. Histology analysis of the nodule removed showed the presence of endometrial tissue which lead to a diagnosis of umbilical endometriosis.

Two months after surgery, the patient had a good postoperative esthetic outcome and no signs of clinical recurrence.

The team emphasizes that clinicians and surgeons when analyzing atypical umbilical nodules and defining possible diagnosis should always consider umbilical endometriosis, regardless of whether they are symptomatic or not, since cyclical symptoms are not always present in this type of condition.