A surgical case report on primary umbilical endometriosis (Villar's nodule).

Endometriosis is a disease characterized by the implantation of endometrial-like tissue outside the uterine cavity. Common symptoms include cyclical pain, dysmenorrhea, dyspareunia, and infertility. Although endometriosis can spread to various extrauterine locations including the ovaries, fallopian tubes, and peritoneal surfaces, umbilical endometriosis is a rare manifestation of the disease. We report an intriguing clinical case of primary umbilical endometriosis in a 36-year-old female patient admitted to our department due to the notable manifestation of a painful swelling at the umbilicus, accompanied by cyclic episodes of bleeding. Subsequent investigations, incorporating ultrasound and computed tomography, indicated the presence of umbilical endometriosis, a finding that was subsequently confirmed by pathological examination of a mass biopsy. Surgical resection of the umbilical mass was performed, and histopathological analysis definitively confirmed the diagnosis of endometriosis. This case report aims to discuss in depth the diagnosis and management of umbilical endometriosis.