Asian Journal of Case Reports in Surgery

Background: Endometriosis is a benign gynecological condition characterized by ectopic endometrial glands and stroma, most commonly affecting pelvic organs. Umbilical endometriosis is a rare extra-pelvic manifestation, and primary (spontaneous) umbilical endometriosis associated with an umbilical hernia can pose a diagnostic challenge, as it may clinically mimic an obstructed hernia.

Case Report: A 38-year-old woman presented with a progressively enlarging nodular swelling at the umbilicus over two years, accompanied by severe cyclical pain during menstruation. Over the preceding six months, the lesion developed pigmentation and cyclical bleeding. Clinical examination revealed a firm, black umbilical nodule measuring approximately 2 × 1.5 cm, with no cough impulse or signs of intestinal obstruction. The clinical features raised suspicion of umbilical endometriosis, which was confirmed on histopathological examination following surgical excision.

Discussion: Umbilical endometriosis is uncommon and often misdiagnosed due to its resemblance to hernia and other umbilical lesions. Imaging modalities such as ultrasonography, computed tomography, and magnetic resonance imaging have limited diagnostic accuracy but can help delineate lesion characteristics and guide surgical planning. Definitive diagnosis is established histologically.

Conclusion: Primary umbilical endometriosis should be considered in women presenting with cyclical umbilical pain, swelling, or bleeding. A high index of clinical suspicion is crucial, and surgical excision remains the treatment of choice with histopathological confirmation.