Gynecologic Imaging History: 14 y.o. female with primary amenorrhea and pelvic pain with a mass. click for a larger image Imaging Findings: Figure A: Transabdominal sagittal ultrasound images of the pelvis demonstrates a large cystic mass with internal echoes inferior to the uterus and posterior to the bladder, in the expected location of the vagina. Figure B: Coronal T2-weighted MR image shows a fluid-filled vagina due to an imperforate transverse vaginal septum. Diagnosis: Hematometrocolpos due to transverse vaginal septum. Discussion: Obstructed ureterovaginal anomalies may be seen either in the newborn period or at puberty (vast majority) with the accumulation of menstrual blood. They are classified into three groups: Mayer-Rokitansky-Kuster-Hauser Syndrome (MRKHS): Agenesis of the uterus and most/all of the vagina (lower 1/3 usually present). Hematometros or hematometrocolpos results if an active uterine anlage (Mullerian duct remnant) is present. Defects of vertical fusion: Descending Mullerian ducts fail to fuse with the ascending urogenital sinus. Result is hematometrocolpos from a vaginal septum, or hematometra from an imperforate cervix, cervical agenesis, or vaginal agenesis with a normal uterus. Transverse vaginal septum is most common and usually at the junction of upper/middle third of the vagina. Disorders of lateral fusion: Result in duplication anomalies with vaginal obstruction most common with didelphys. Unilateral obstruction is a diagnostic dilemma because "normal menses" flow from the nonobstructed side. Symptoms include bulging hymen, intralabial mass (low vaginal obstruction), abdominal mass, cyclic abdominal pain, primary amenorrhea, voiding dysfunction, ambiguous genitalia. Imaging: Ultrasound and MRI are roughly equal at diagnosis but MRI is superior at characterization due to multiplanar capability and soft tissue resolution and is preferred for MRKHS and disorders of lateral fusion. The vagina is much more distensible than the uterus allowing distinction by ultrasound of -colpos from -metrocolpos. Ultrasound identifies hematosalpinx which increases the patient's risk for endometriosis. Ultrasound, especially transperineal, helps with sugical planning by identifying the length of the atretic segment to determine if an indwelling form must be placed following resection. The atretic segment tends to be longer with higher septa. Also, ultrasound evaluates the presence and patency of the cervix. With cervical agenesis, the vaginal tapers to a blind pouch. When hematometra is seen, nonvisualization of the (fluid-filled) endocervical canal means the cervix is imperforate. Ultrasound also aids in the medical management by detecting renal anomalies, follow-up of hydronephrosis and endometriosis (complication of delayed diagnosis), and documents decompression after surgery. References: Blask AR, et al. Obstructed Ureterovaginal Anomalies: Demonstration with ultrasound. Radiology 1991; 179(1):84-8. Scanlan KA, et al. Value of Transperineal Sonography in the Assessment of Vaginal Atresia. AJR 1990;154(3):545-8. Woodward PJ, et al. Congenital Uterine Malformations. Current Problems in Diagnostic Radiology 1995; 24(5):178-97. Submitted by: Mark Geist, MD TOP