Many gynecologists encounter imperforate hymen, a congenital vaginal anomaly, in general practice. As such, it is important to have a basic understanding of the condition and to be aware of appropriate screening, evaluation, and management. This knowledge will allow you to differentiate imperforate hymen from more complex anomalies—preventing significant morbidity that could result from performing the wrong surgical procedure on this condition—and to provide optimal surgical management.
How often and why does it occur?
The hymen consists of fibrous connective tissue attached to the vaginal wall. In the perinatal period, the hymen serves to separate the vaginal lumen from the urogenital sinus (UGS); this is usually perforated during embryonic life by canalization of the most caudal portion of the vaginal plate at the UGS. This establishes a connection between the lumen of the vaginal canal and the vaginal vestibule.3 Failure of the hymen to perforate completely in the perinatal period can result in varying anomalies, including imperforate (FIGURE 1), microperforate, cribiform, or septated hymen.
Figure 1. Imperforate hymen
How does it present?
In infancy. Newborns typically will present with a hymenal bulge from hydrocolpos or mucocolpos, which result from maternal estrogen secretion on the newborn’s vaginal epithelium.5 This is usually asymptomatic and self limited.
Rarely, large hydrocolpos/mucocolpos may become symptomatic and can lead to urinary obstruction, or they can present as an abdominal mass or intestinal obstruction.4
In adolescence. The majority of adolescents will present with cyclic or persistent pelvic pain and primary amenorrhea. If significant hematometra is present, an abdominal mass also may be palpated. In extreme cases, the patient may present with mass effect symptoms, including back pain, pain with defecation, constipation, nausea and vomiting, urinary retention, or hydronephrosis.6 Retrograde passage of blood into the fallopian tubes can cause hematosalpinx, which can lead to endometriosis and adhesion formation. Blood also may pass freely into the peritoneal cavity, forming hemoperitoneum.3
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Robert L. Barbieri, MD (October 2012)
Imperforate hymen, vaginal septum, or distal vaginal atresia?
When in doubt, refer. Imperforate hymen can be confused with distal vaginal atresia or low transverse vaginal septum. Often, the patient may present with similar signs and symptoms in all 3 cases. Accurately differentiating imperforate hymen from the former two more complex congenital anomalies prior to surgery is of utmost importance because management is very different, and performing the wrong procedure can result in serious morbidity. As such, it is important to appropriately define the anatomy and refer the complex cases to a specialist comfortable and skilled in managing congenital anomalies, usually a pediatric and adolescent gynecologist or reproductive endocrinologist.
Examination of the external genitalia reveals a perineal bulge secondary to hematocolpos.7 This finding, coupled with a rectal examination and pelvic ultrasonography is usually sufficient to make the diagnosis.6,8 However, magnetic resonance imaging (MRI) of the pelvis should be obtained in cases where the diagnosis is uncertain or the physical exam is more consistent with vaginal septum or agenesis.
Transverse vaginal septum
A reverse septum results from failure of the müllerian duct derivatives and UGS to fuse or canalize. This can occur in the lower, middle, or upper portion of the vagina, and septa may be thick or thin.6 Low transverse septa are more easily confused with imperforate hymen. Examination usually reveals a normal hymen with a short vagina posteriorly. In cases of extreme hematocolpos, vaginal septa also may present with a perineal bulge but, again, this will be posterior to a normal hymen.
Distal vaginal atresia
This condition occurs during embryonic development when the UGS fails to contribute to the lower portion of the vagina (FIGURE 2).5 In cases of distal vaginal atresia there is a lack of vaginal orifice, or only a vaginal dimple may be present.5,6 Rectovaginal examination will reveal a palpable mass if the upper vagina is distended with blood.6