Beyond the pelvis: A case of umbilical endometriosis

A 34-year-old woman, gravida 2 para 2, presented with a 1-year history of cyclical umbilical bleeding. She reported no other associated symptoms, such as pelvic pain, dysmenorrhea, or abnormal uterine bleeding. Her medical and surgical history was non-contributory. There was no significant family history of endometriosis or other gynecological conditions. Dermatologic examination revealed a non-ulcerated, 1.5 cm brown nodule at the umbilicus. The rest of the physical examination was unremarkable. Given the patient's history of cyclical umbilical bleeding and the presence of a palpable umbilical nodule, a pelvic MRI was performed. The imaging study revealed an umbilical nodular formation measuring 15 × 7 mm, showing hyperintensity on T2-weighted, T1-weighted, and T1 fat-saturated sequences ( Fig. 1 ). There was also thickening of the uterosacral ligaments ( Fig. 2 ). Fig. 1 Axial T2 (A), sagittal T2 (B), axial T1 (C), and axial T1 fat-saturated (T1FS) sequences demonstrated a parietal nodule located at the umbilicus (red arrow), exhibiting high signal intensity on T2-weighted, T1-weighted, and T1 fat-saturated images, measuring 15 × 7 millimeters. Fig 1: Fig. 2 Axial T2-weighted image showing a thickening of the torus (red arrow), suggestive of deep endometriosis. Fig 2: Axial T2 (A), sagittal T2 (B), axial T1 (C), and axial T1 fat-saturated (T1FS) sequences demonstrated a parietal nodule located at the umbilicus (red arrow), exhibiting high signal intensity on T2-weighted, T1-weighted, and T1 fat-saturated images, measuring 15 × 7 millimeters. Axial T2-weighted image showing a thickening of the torus (red arrow), suggestive of deep endometriosis. A routine blood test was performed to rule out any underlying systemic conditions. All laboratory results, including complete blood count (White blood cell count : 8000 cells/µL [Normal range: 4500 - 11,000 cells/µL], Hemoglobin (Hgb): 13.0 g/dL [Normal range: 12.0-16.0 g/dL for women], Platelet count: 250,000 cells/µL [Normal range: 150,000 - 450,000 cells/µL], comprehensive metabolic panel, and inflammatory markers, were within normal limits. The biopsy revealed endometrial tissue, including glands, stroma, and smooth muscle, in an ectopic location, consistent with endometriosis. The patient was referred to gynecology for surgical management. Laparoscopic surgery is typically the gold standard for treating endometriosis, allowing for precise excision of the ectopic endometrial tissue.

Consent was obtained from the patient for publication of this case report and accompanying images.

Umbilical endometriosis is an uncommon condition. It should always be considered in the presence of an umbilical mass associated with cyclic symptoms, prompting appropriate management

Endometriosis refers to the abnormal presence of endometrial tissue outside the uterine cavity. Umbilical endometriosis, also known as Villar's nodule, is a rare extra-pelvic manifestation of endometriosis. Its prevalence is estimated to be around 1% of all endometriosis cases. It predominantly affects women of reproductive age. It is rare before menarche and tends to decrease after menopause [ 4 ]. Umbilical endometriosis has been very rarely described in the literature, and often occurs at the site of a surgical scar in previously operated women [ 5 ]. Its pathogenesis remains poorly understood. Proposed etiological theories suggest a role for coelomic metaplasia, the presence of congenital displaced endometrial tissue during development, direct extension via the round ligament or the omphalomesenteric duct, or mechanical seeding of endometrial tissue via the lymphatic or venous system [ 6 ]. Clinically, it manifests as a painful umbilical mass with cyclical bloody discharge. The cyclical nature, coinciding with menstruation, is a key feature and can often be sufficient to suggest the diagnosis [ 5 ]. As reported in the literature, our patient exhibited similar cyclical bloody umbilical discharge. Even if the certitude diagnosis remains anatomopathological, MRI findings are critical in distinguishing endometriotic umbilical nodules from other diagnoses. On T2 and T1 weighted sequences, masses with a strong glandular component and a weak fibrous reactivity appear hyperintense with enhancement after gadolinium injection. Fibrous lesions are hypo or isointense on T1 and T2, with varied and frequently mild enhancement, whereas mixed masses present as fibrous masses with punctiform T1 and T2 hyperintense patches [ 4 ]. Our patient's MRI demonstrated a 15 × 7 mm umbilical nodule exhibiting hyperintensity on T2, T1, and T1 fat-suppressed sequences. Histopathological examination reveals ectopic endometrial glands with glandular tubules, cytogenic stroma, and smooth muscle fibers [ 7 ]. Treatment for umbilical endometriosis is surgical. The gold standard involves wide excision of the mass with at least a 1 cm margin to reduce the risk of recurrence. An exploratory laparotomy or laparoscopy can be performed through a subumbilical incision to rule out other pelvic sites of endometriosis without additional risk [ 3 ].

Umbilical endometriosis is a rare clinicopathological entity. It typically occurs between the ages of 35 and 38 years [ 1 ]. Catamenial pain and bleeding usually guide the diagnosis. The main differential diagnoses of umbilical endometriosis include umbilical hernia, nodular melanoma, primary or metastatic cancers, granulomas, and keloids [ 2 ]. Its pathogenesis remains poorly understood. Proposed etiological theories suggest a role for coelomic metaplasia, the presence of congenital displaced endometrial tissue during development, direct extension via the round ligament or omphalomesenteric duct, or mechanical seeding of endometrial tissue via the lymphatic or venous system. Treatment is primarily surgical [ 3 ].