Primary Extrapelvic Umbilical Endometriosis Presenting With Cyclical Umbilical Bleeding: A Case Report.

Primary extrapelvic endometriosis is the presence of endometrial tissue in sites outside the uterine cavity in an individual who has had no prior abdominal surgeries. Various theories have been postulated to describe the etiology of endometriosis. Our case study involves a multiparous patient in her late 40s with no prior abdominal surgeries who presented with bleeding from her umbilicus associated with swelling and pain corresponding to her menstrual cycle. A computed tomography scan of the abdomen detected a homogenous granuloma-like umbilical soft tissue mass. The umbilical nodule and the umbilicus were excised, and the specimen was sent for histopathological examination that validated the diagnosis of an umbilical endometrioma by revealing endometrial glands with stroma involving the dermis. Postoperatively, the patient was symptomatically better and was discharged. Primary umbilical endometriosis can mimic conditions like omphalitis, umbilical granuloma, and umbilical hernia; hence, it is important to understand how to differentiate this case from other diagnoses. This case contextualizes that the likelihood of primary umbilical endometriosis in such unusual presentations must always be considered.