Imperforate Hymen

Etiology

During urogenital development, the cloaca is divided by the urorectal septum to separate the ventral urogenital sinus from the dorsal anal canal. The Wolffian ducts (mesonephric ducts) and Müllerian ducts (paramesonephric ducts) are the two main ductal systems that give rise to specific structures in the male and female genital and urinary tracts. The Wolffian duct develops from the paired urogenital ridges and grows caudally to induce the formation of mesonephric tubules. Additionally, the Wolffian duct induces the development of the Müllerian ducts from the coelomic epithelium of the paired urogenital ridges. The Müllerian ducts grow caudally using the Wolffian ducts as guides. The close association of the Müllerian ducts and Wolffian ducts during development explains the high incidence of urinary tract anomalies in women who also have Müllerian anomalies. The fusion of the Müllerian ducts forms the uterovaginal canal that gives rise to the uterus, cervix, and upper two-thirds of the vagina. The distal point of contact of the Müllerian ducts with the urogenital sinus is the site of the proliferation of the urogenital sinus epithelium, forming the sinovaginal bulb. The sinovaginal bulb develops into the vaginal plate.[5]

The embryological origin of the lower third of the vagina is the urogenital sinus. The precise embryological origin of the imperforate hymen is controversial. It is thought that the hymen normally perforates at approximately 22 weeks gestation. The most popular theory is that the hymen may fail to canalize with the rest of the vagina during development when the sinovaginal bulbs canalize at the site where the uterovaginal canal meets the urogenital sinus.[6][7] The imperforate hymen results from unsuccessful canalization of the vaginal plate and failed degeneration of the hymenal epithelial cells.[6] The hymen is likely derived from urogenital sinus posterior wall invaginations.[8]

Redundancy of the newborn hymenal tissue leading to an inverted appearance is a common finding at birth, and over half of newborn females will have reduced tissue redundancy by 1 year of age.[9][10] As the influence of maternal estrogen subsides, the hymenal opening expands and may adopt a crescentic appearance.[10] Hymenal tags may spontaneously resolve and may also appear where there were no previous tags.[10] A study of 468 newborns showed a significant difference in hymenal characteristics by race but not gestational age or weight.[9] At birth, the most common normal hymenal types are the annular and fimbriated forms.[9] Other hymenal variations that are considered abnormal include microperforated, septate, and cribriform hymens.[11]

Microperforate hymen is thought to result when epithelial cells in the center of the developing hymen do not normally degenerate.[6] As the hymen is not a Müllerian structure, there is not a high likelihood of urinary tract anomalies associated with imperforate hymen. Exceptions to this speculation are reported in the literature in case reports. However, these instances are likely due to random embryologic events.[12][13][14] While many imperforate hymen cases are considered isolated incidences, there are reports of familial occurrence of the imperforate hymen in autosomal dominant, autosomal recessive, and polygenic inheritance patterns.[8][15]

Epidemiology

The incidence of imperforate hymen is estimated to be 1 in 1000 female births.[16] The prevalence of urinary tract anomalies ranges from 4.2 per 10 000 births to 4.0 per 1000 births in studies of birth registries from various countries in Europe and Asia.[17][18][19][20][21][22] Unlike the higher incidence of renal anomalies in patients with Müllerian abnormalities, such anomalies associated with an imperforate hymen is extremely rare. This overall rarity explains why the condition of multiple anomalies with imperforate hymen is primarily documented in case reports. However, the incidence of urinary retention and acute kidney injury associated with imperforate hymen on presentation is approximately 20% and 2%, respectively.[8] The incidence of other hymenal abnormalities is unknown, with approximately 20 case reports of microperforate hymen noted in the literature.[23]

Histopathology

The hymen is minimally innervated and predominantly consists of fibrous connective tissue with elastic fibers and glycogen granules on the vaginal and vulvar surfaces. Both of its surfaces are surrounded by stratified squamous epithelium without glands.[24] This stratified squamous epithelium on histology serves as supporting evidence for the non-Müllerian origin of the hymen, as the distal third of the vagina is derived from the urogenital sinus and is also lined by stratified squamous epithelium.

History and Physical

The presentation of an imperforate hymen is variable, depending on the patient’s age at presentation, the severity of the obstruction, and the clinical course. Additionally, the evaluation of the prepubescent child differs from the evaluation of the adolescent female. Abnormalities of the female genitalia may be difficult to discern on the newborn physical exam due to the excess hymenal tissue.

Hydronephrosis and pelvic masses can be detected as early as the 20-week prenatal ultrasound.[4] In interviews with patients’ parents, fever and fussiness are commonly reported. Parents may also report no abnormalities in voiding behavior. Infants may have mucocolpos from the accumulation of vaginal and cervical gland secretions due to endogenous maternal estrogen stimulation. Early pediatric presentations may include urinary retention, hydronephrosis with a urinary tract infection, or acute lobar nephronia from urinary tract obstruction.[25] 

Infants with imperforate hymen may not demonstrate a perineal bulge on physical exam. The imperforate hymen may be subtle, even if ultrasound demonstrates bilateral hydronephrosis with a bladder distended to the umbilicus.[8] Therefore, the history and physical examination should be performed diligently with suspicion of this disorder. The common redundancy of the newborn hymenal tissue explains why hymenal abnormalities may be missed on the newborn exam.

During the interview of the mature adolescent, clarifying the menstrual and coital history is important since patients may report regular menses with a microperforate hymen. Cyclic monthly pain is often reported due to menstrual blood that expands the vaginal canal and uterus with resultant hematometra. Expansion can cause numerous pelvic symptoms, including pelvic and back pain, constipation, radiated pain secondary to sacral plexus irritation, and urinary retention.[8] Up to 3 liters of retained blood have been reported in cases in the literature.[26] Urethral coitus is a rare presentation of an imperforate or microperforate hymen due to accidental penetration of the urethra during intercourse, even if the patient denies issues with vaginal penetration and dyspareunia. Symptoms may also include coital incontinence and recurrent urinary tract infections.[27] 

The female genital exam starts with identifying external structures to avoid overlooking anomalies before attempting a speculum exam. The physical examination of the adolescent may demonstrate a blue, bulging perineal mass that enlarges with the Credé maneuver. The Credé maneuver, application of manual pressure on the lower abdomen, exposes the imperforate hymen as a vaginal bulge.[4] If a hematosalpinx ruptures, the abdominal exam will demonstrate peritonitis.[28] The rectal exam may uncover a tender fluctuance posterior to the vagina and may reveal if there are absent structures proximal to the vagina.

Evaluation

Routine prenatal ultrasound at 20 weeks of gestation is a cost-effective method for evaluating the fetus’s urinary tract for renal abnormalities, duplex kidney, or hydronephrosis of various etiologies, including physiologic hydronephrosis or obstruction, urinary retention, and vesicoureteral reflux.[12] After delivery, pelvic ultrasound is critical in evaluating imperforate hymen to identify hematocolpos and associated urinary tract obstruction, such as a distended bladder and/or hydronephrosis. Pertinent findings on ultrasound may be further evaluated with magnetic resonance imaging (MRI), the gold standard for assessing anatomical abnormalities.[22] Given that a large pelvic mass can obscure pelvic anatomy, it is recommended to obtain a postoperative MRI if there is any concern for other urogenital anomalies.[14][29]

Treatment / Management

Spontaneous rupture of the asymptomatic imperforate hymen has previously been reported in 1-day-old to 1-month-old infants.[16] Ideally, this condition would be identified on the newborn physical examination so that asymptomatic patients could be managed expectantly before menarche.[2] However, patients with undiagnosed imperforate hymen often present acutely and require urgent surgical intervention to control symptoms and prevent abdominal complications, such as retrograde menstruation, endometriosis, and/or fertility complications. Definitive hymenectomy under anesthesia must be performed for drainage and relief of symptoms rather than an in-office hymenotomy. It is crucial to not temporarily decompress the pelvic mass in the office through incision and drainage before definitive hymenectomy. Any incision performed outside the operating room risks developing iatrogenic pelvic inflammatory disease and subsequent reclosure of the hymen.[30](B3)

Other genital anomalies may be discovered at presentation. Identifying an imperforate hymen prior to an acute presentation may assist with planned hymenectomy. Ideally, surgery should be deferred until puberty when the vaginal tissue is adequately estrogenized, which promotes wound healing following surgical incision of the hymenal tissue. Treatment options for an imperforate hymen include:

1. Hymenectomy using cruciate or annular incisions
2. Hymenectomy using electrocautery
3. Placement of a 16Fr Foley catheter with 10 ml balloon insufflation to preserve hymenal tissue
4. Carbon dioxide laser treatment

Purulent vaginal fluid on needle aspiration may be discovered before drainage, which suggests that the hydrometrocolpos may be infected even before surgical intervention.

The traditional method of hymenectomy entails making a cruciate incision (cross-shaped) over the hymenal tissue with excision of the quadrants and approximation of the hymenal edges to the vestibule with absorbable sutures. Other methods reported in the literature include hymen-sparing techniques. Annular hymenotomy using electrocautery to perform a circumferential annular (ring-shaped) hymenotomy had no postoperative hymenal closure or scarred tissue beyond the hymenal contour in 14 patients aged 14.2 +/- 2.2 years at the time of surgery.[31] Another hymen-preserving technique used in a cohort of 65 patients aged 13.9 +/- 2.1 years involved making a 0.5 cm incision to accommodate an indwelling 16rF Foley catheter for 2 weeks with daily application of estrogen vaginal cream to promote epithelization. There were no reported infectious complications, but reclosure of the hymen was noted in 2 of the 65 women. This complication was attributed to patient noncompliance with estrogen cream application.[32] It is recommended that prepubescent patients apply topical estrogen due to the risk of spontaneous hymenal reclosure after surgery.[4] Hymenal reclosure may be associated with ascending infection and reproductive complications. A study of 13 patients aged 12 to 16 years who underwent carbon dioxide laser treatment under local anesthesia to create a new orifice resulted in no scarring or hymenal stenosis at the 2-week postoperative follow-up without estrogen cream and without report of dyspareunia at 18 months.[33] (B2)

The traditional treatment for microperforate hymen includes cruciate hymenectomy.[23] An alternative, novel treatment option in patients who do not have infectious symptoms or acute obstruction is using Hegar dilators to progressively dilate the vaginal introitus in the operating room under general anesthesia. The 2 patients who have undergone this technique had satisfactory outcomes without scarring and with subsequent easy use of tampons. No information on dyspareunia was reported.[6] In a septate hymen where the remnant hymenal tissue is not entirely obstructive, resection of the septum after tying both ends with absorbable suture using topical lidocaine cream in the office is appropriate.[34](B3)

Differential Diagnosis

The differential diagnosis for a perineal mass in a newborn female includes a periurethral cyst, ectopic ureterocele prolapse, and vaginal botryoid sarcoma. Imperforate hymen is distinguished from a periurethral cyst by identification of the urethral meatus. Ectopic ureteroceles may prolapse from the urethra and have a congested appearance. Vaginal botryoid sarcoma typically has a multilobulated appearance.[35]

Other vaginal anomalies that result from developmental aberrancies of the urogenital sinus and Müllerian ducts must be distinguished from imperforate hymen and can also rarely occur in association with an imperforate hymen. Failure to diagnose these anomalies burdens the patient with further morbidity because the treatments differ. These main abnormalities include a transverse vaginal septum, vaginal atresia, and vaginal agenesis.

Failure of canalization at the point of contact between the urogenital sinus and the Müllerian ducts results in a transverse vaginal septum. Transverse vaginal septa can be located at different levels within the vagina (upper, middle, and lower). The septa may be associated with small perforations.[36] Vaginal agenesis is the congenital absence of the proximal vagina and may be associated with agenesis or hypoplasia of other Müllerian duct derivatives, including the fallopian tubes, uterus, and cervix. The cause of isolated vaginal agenesis is less well-defined, but when both the Müllerian tubercle and ducts are involved, the result is Mayer-Rokitansky-Küster-Hauser syndrome. Women with MRKH syndrome may or may not have a hymen.[11]

Vaginal atresia results from an aberrancy in the urogenital sinus, possibly recanalization, such that there is a septum or stenosis. While patients with vaginal agenesis may not be able to conceive due to hypoplasia or the absence of the fallopian tubes and uterus, pregnancy is possible for women with vaginal atresia after surgical correction. A rectal exam can help define the extent of the genital tract in children and assess if there are vaginal septa or anomalies.[16] MRI is the gold standard for evaluating the pelvis and ruling out other Müllerian anomalies.[22] 

Imperforate hymen can present as part of a syndrome, such as McKusick-Kaufman syndrome, characterized by polydactyly, congenital heart disease, and hydrometrocolpos in females.[37] Hydrometromolpos can be caused by any obstructive anomaly of the female genital tract, including imperforate hymen or other anomalies, such as vaginal agenesis or vaginal atresia.

Hymenal polyps, which can occur in newborns, are also in the differential diagnosis. These polyps are benign and disappear spontaneously within a few weeks of birth.[38] 

Prognosis

Successful treatment of an imperforate hymen satisfactorily resolves symptoms. Rarely the imperforate hymen has been associated with neonatal death due to respiratory failure from abdominal distension.[39] Even with postoperative infection following hymenectomy, hymenal patency remains satisfactory.[4] The theoretical risk of dyspareunia is not well-elucidated in the literature. Adolescents treated with Foley catheter insertion to preserve the hymenal structure did not complain of severe dyspareunia at first coitus on follow-up.[32] At an average follow-up period of 8.5 years, women who underwent hymenectomy reported dysmenorrhea without complaints of sexual dysfunction. Successful live birth was reported among those that attempted pregnancy.[40] 

In another study, 86% of women experienced no dyspareunia and conceived after hymenectomy.[41] Dysmenorrhea is likely due to pelvic endometriosis from retrograde menstruation in women with imperforate hymen.[40] A long-term follow-up of 40 patients with either imperforate hymen or transverse vaginal septa found that patients with imperforate hymen had significantly better rates of successful term pregnancies.[41]

Vaginal adenocarcinoma is rare and was reported in a patient with vaginal adenosis and a prior history of imperforate hymen. Vaginal adenosis, the persistence of columnar epithelium in the vagina, was reported on colposcopic biopsies 2 years after hymenectomy in a 13-year-old patient who did not have estrogen exposure in utero. Another 20-year-old female who underwent hymenectomy and was found to have granulated vaginal walls had a colposcopy with biopsies positive for vaginal adenosis, which can be a precursor to vaginal adenocarcinoma. Another 14-year-old female presented for vaginal discharge and was found to have a red granulated vaginal wall with biopsies demonstrating adenosis. The authors hypothesized that vaginal adenosis associated with imperforate hymen may be related to undifferentiated paramesonephric tissue during development.[42]

Complications

Iatrogenic pelvic inflammatory disease has been documented after a patient underwent an office hymenotomy under sterile conditions. The surgical site spontaneously sealed within 1 day when the patient was evaluated by an adolescent gynecologist who scheduled a hymenectomy in the operating room 2 days later. However, on postoperative day 7, the patient had a high-grade fever and lower abdominal pain, with MRI demonstrating a  right pyosalpinx requiring CT-guided drainage. This account illustrates that even small incisions into an imperforate hymen for symptomatic relief or confirmation of diagnosis should not be undertaken due to the risk of iatrogenic infection from inoculation of bacteria into the hematocolpos.[30] Therefore, a patient who needs an urgent hymenectomy due to infection or urinary tract obstruction should have the procedure performed definitively in the operating room under sterile conditions.

Hymenal reclosure is a risk, thought to be increased in prepubertal patients due to a lack of estrogenization of genital tissue.[4] Hymenal reclosure was documented in a 2-day-old infant who initially underwent bedside incision and drainage in the neonatal intensive care unit with same-day discharge, only to present at 3 weeks with perineal swelling and a bulging hymen. The infant underwent an annular hymenectomy in the operating room with sutures to approximate the hymenal margins to the vestibule. Here, the authors comment on using a suture or dilator at hymenectomy to decrease reclosure risk.

Another case report of a 16-year-old patient who required 4 hymen surgeries due to reclosure had a Foley catheter placed for 3 to 4 days after the first 3 surgeries and, on her fourth presentation, underwent hymenectomy with continuous locked sutures and catheter placement for 14 days. No estrogen cream use was documented.[7] This case’s use of a Foley catheter is compared to Acar et al’s Foley catheter method, in which catheters were placed for 2 weeks with daily application of estrogen cream in a cohort of females aged 13.9 +/- 2.1 years. Inadequate hymenectomy with stenosis and closure is thought to contribute to developing dyspareunia and infertility.[43]

Postoperative infection risk is not globally studied, but individual case reports and series outcomes are reported. The decision to administer preoperative antibiotics is surgeon-specific and depends on patient factors, such as concern for possible pyosalpinx.[31] While not all surgeons administer preoperative antibiotics, hematocolpos is believed to provide a medium for bacteria to flourish within the anaerobic uterine environment.