Case report: A rare case of congenital vulvar malformation that is often overlooked

Abstract Purpose This study explores the clinical features, diagnostic criteria, and optimal timing for surgery in primary labia minora fusion, a rare congenital vulvar malformation, emphasizing that appropriate surgical timing can reduce the impact of retrograde menstrual flow and minimize long-term complications. Methods Retrospective analysis of clinical data from a 17-year-old patient with primary labia minora fusion. Results The patient underwent labiaplasty and perineal reconstruction, with good postoperative recovery. Dysmenorrhea symptoms were significantly alleviated compared to preoperatively, and the patient is able to resume normal sexual activity. Conclusion Primary labia minora fusion is extremely rare and is often mistaken for an anatomical variation that does not affect health. However, this deformity can cause functional low vaginal obstruction, resulting in retrograde menstrual flow and progressive dysmenorrhea, and increasing the risk of subsequent endometriosis. Once diagnosed, it is recommended to undergo surgical reconstruction as soon as possible, rather than postponing it until sexual intercourse becomes difficult or severe symptoms occur.