Hematocolpos Presenting as Acute Urinary Retention: When Gynecologic Pathology Mimics Urologic Disease.

An imperforate hymen is a rare congenital anomaly that typically presents at puberty with cyclic lower abdominal pain, primary amenorrhea, and, in severe cases, acute urinary retention secondary to mass effect from hematocolpos or hematometra. We report the case of a 13-year-old girl who presented with a 24-hour history of urinary retention, preceded by two months of dull lower abdominal pain, pressure, and dysuria. Pelvic ultrasound demonstrated a large, well-circumscribed cystic mass posterior to the bladder with internal echoes and endometrial thickening. Magnetic resonance imaging (MRI) confirmed a markedly distended vagina with blood signal characteristics consistent with hematocolpos. The patient underwent a cruciate hymenectomy under general anesthesia with evacuation of approximately 600 mL of retained blood. In adolescent girls presenting with primary amenorrhea, cyclic pelvic pain, and urinary complaints, an imperforate hymen with resultant hematocolpos should be considered in the differential diagnosis. Prompt diagnosis and surgical management provide rapid symptom relief and prevent urinary and reproductive complications.