Labium Majus Ectopic Pregnancy: Diagnostic and Therapeutic Implications of a Rare Obstetric Phenomenon—A Case Report

Ectopic pregnancy occurs when a fertilized ovum implants outside the uterine cavity, most commonly in the fallopian tube. While rare, ectopic pregnancies can also occur in atypical locations such as the ovary, cervix, abdominal cavity, or broad ligament, often posing significant diagnostic and therapeutic challenges. We report a highly unusual case of ectopic pregnancy implanted in the left labium majus, a site not previously documented in the literature. A 20-year-old woman presented with abdominal pain, vulvar swelling, and amenorrhea of approximately 4 months. Initial imaging and clinical evaluation did not reveal the ectopic implantation. Diagnosis was made intraoperatively during marsupialization of the vulvar swelling, which revealed a macerated fetus within the left labium majus. This case highlights the importance of maintaining a high index of suspicion for rare ectopic pregnancy sites in patients presenting with unexplained vulvar symptoms and a positive pregnancy test-particularly when imaging is inconclusive. It underscores the critical role of prompt surgical exploration in preventing life-threatening complications and contributes to expanding the clinical spectrum of ectopic pregnancy presentations.