Extrapelvic endometriosis is a rare and complex phenomenon. Endometriosis has been reported in several organs including the brain, lungs, gastrointestinal tract, urinary system and muscles. Despite about 12% of patients with endometriosis have extrapelvic disease, it is usually misdiagnosed^1,2.

We report a case of primary umbilical endometriosis, a condition that was first described by Villar in 1886³. The patient sought medical care in our department after several medical visits with diagnosis of “infection” of the umbilical scar unresponsive to medical treatment.

The patient was a 29-year-old nullipara, with no relevant medical or surgical history, who complained of episodic stabbing pain in the umbilicus, which partially relieved with nonsteroidal anti-inflammatory drugs. Interestingly, 24 to 48 hours after the last day of menstruation she noted a small amount of bloody discharge along with a change in the color of the umbilicus which became “darker”.

The physical examination revealed a 1.5-cm soft umbilical nodule, fixed to the deep plane, with a slightly darker color than the rest of the skin (Fig. 1).

Figure 1 Villar’s nodule (held by a Backhaus forceps) 

A diagnosis of Villar’s nodule was made and the patient underwent abdominal ultrasound, transvaginal ultrasound and soft tissue mass ultrasound of the umbilical region which reported: “solid echogenic subcutaneous nodule with well-defined borders and a small central cystic area”. The gynecologic scans did not show any other lesions.

As it was impossible to obtain an MRI of the abdomen and pelvis at the time of menstruation for disease staging, we decided to perform an exploratory laparoscopy. Small implants were found in the Douglas’ pouch and there were no other lesions. The lesion was resected, preserving the umbilicus (Fig. 2).

Figure 2 Specimen of resection 

The patient had favorable postoperative outcome and was discharge 24 hours later. She is receiving hormone treatment, is followed-up by the department of gynecology, and is free of recurrence after 5 months.

The pathology report concluded: “epidermis with focal erosion; ectopic endometrial glands lined with a row of low cylindrical cells in the underlying stroma. Histological features of endometriosis”.

In general, cutaneous or subcutaneous involvement of endometriosis is secondary to a surgical scar. Less than 30% of cases of cutaneous endometriosis appear in the absence of surgery and are known as primary or spontaneous cutaneous endometriosis^2,5 as in our patient, may even develop during pregnancy and disappear spontaneously after childbirth. Umbilical endometriosis represents 0.4 to 4% of endometriosis⁴. Its pathogenesis is not well understood but may arise from endometrial tissue that reaches the umbilicus via the blood vessels or lymphatic system, or by direct seeding during laparoscopy that may then proliferate^1,3,4.

Umbilical endometriosis usually appears as single or multiple solid nodules (rarely multilobulated), with a diameter between 0.5 and 2.5 cm, varying in color according to the amount of blood and the degree of penetration of the ectopic endometrial tissue. Occasionally skin-colored nodules can develop². Mean age of patients is between 33 and 39 years according to the different series². Clinical symptoms include pain, bleeding, hyperesthesia, edema and nodule enlargement during menstruation. All symptoms rarely appear together, and even asymptomatic cases have been reported. Gynecologic symptoms (dysmenorrhea, dyspareunia, infertility and pain) are absent in cutaneous endometriosis². The differential diagnoses include hernia, pyogenic granuloma, polyps, keloid and primary and metastatic neoplasms (often wrongly diagnosed as melanoma)^1,2,4,5. The diagnosis is based on the medical history, physical examination and clinical suspicion. The complementary tests help to offer the best therapeutic approach and may be useful or not to diagnose it. In these cases “clinical findings remain paramount” and soft tissue mass ultrasound, computed tomography scan or magnetic resonance imaging can help with the diagnosis^1,2,5. Surgery with or without omphalectomy is the treatment of choice with wide resection to ensure definite cure. Some authors use laparoscopy during resection to detect deep endometriosis, which should be excluded in patients with pelvic symptoms^1-5. The final diagnosis is confirmed by the pathological examination^1-3.

The prognosis is favorable and recurrences are uncommon. Malignant transformation has been reported in 0.3-1% of the cases and should be suspected in case or recurrence or rapid growing lesions^2,4.