Arcuate uterus and heart-shaped uterine fundus lie at the most minor end of the spectrum of müllerian fusion anomalies of the uterus, manifesting as incidental findings on ultrasound scan or at cesarean section. The arcuate uterus is noted to have a top that is flat rather than convex, and the heart-shaped uterus has an indentation at the fundus. Neither of these conditions generally requires any intervention, although they may occasionally be associated with abnormal fetal lie in late pregnancy.
A more significant anomaly on the müllerian fusion spectrum is the bicornuate uterus, which has two independent uterine canals. There may be a common vagina, or two distinct vaginas. Patients may present with difficulty inserting tampons, or with dyspareunia. This may confuse the unwary health-care provider when performing vaginal examination. The condition may also be associated with abnormal fetal lie in pregnancy, and/or premature labor.
One variant is the uterine anomaly known as communicating uteri, where an isthmic communication connects two separate uterocervical cavities.[8, 9]
In situations where one vagina is blind ending, the young woman will present with severe dysmenorrhea. As she will be menstruating via the unaffected vagina, it may be many months, or even years, before the condition is recognized. Treatment consists of surgical removal of the septum. This creates a single vagina, which naturally contracts to a normal vaginal caliber. Nine different forms of this uterine anomaly (with variations) have been described by Toaff et al.[8] A representative example is seen in Figure 33-2.
Toaff type 5 A communicating uterine anomaly, one of several forms of the communicating uterine malformation. The patient in this example also had an endometrioma on the side of the obstructed hemivagina.
A unicornuate uterus occurs through normal development of only one müllerian duct. It may be associated with abnormal fetal lie and premature labor. Occasionally, a rudimentary uterine horn may coexist with a unicornuate uterus. If the canal of the horn is blind ending (not communicating with the main uterine body), then severe dysmenorrhea will occur as the horn fills cyclically with menstrual fluid. The modern treatment is excision of the rudimentary horn, which is generally carried out laparoscopically. In years gone by, attempts were made to join the two horns together surgically, but the outcomes were not as good as with resection.[10] If pregnancy occurs in a rudimentary uterine horn, uterine rupture may occur, with potentially catastrophic results.
The most severe of the müllerian anomalies is Mayer-Rokitansky-Kuster-Hauser syndrome (MRKH), where the uterus and the upper vagina fail to develop as a consequence of failure of migration of both the wolffian and müllerian ducts.[11, 12] Development of secondary sexual characteristics takes place, as the ovaries are present, and there is characteristically no suspicion of a problem until primary amenorrhea is experienced. The incidence is approximately 1 in 5,000 female births.
Ultrasound evaluation of these patients will reveal an absent uterus with ovaries, which may be more difficult to see than usual, as they may be situated laterally, on the pelvic sidewall. MRI will be required to more accurately define the findings, and to delineate the amount of vagina present.
Three main areas of concern for patients with MRKH are psychological, sexual, and reproductive.
The diagnosis is potentially devastating for the patient and her family. Discussion must be handled very sensitively, with input from a clinical psychologist. For most patients, puberty will have progressed normally prior to the recognition of primary amenorrhea; the diagnosis is thus likely to be sudden and completely unexpected for the patient and her family. This generates serious concerns and anxieties in relation to body image as well as to sexual function and future reproductive potential.
The first-line treatment for creating a neo-vagina is the use of vaginal dilators. The success of this treatment is dependent on compliance, as 30 minutes of treatment daily on a regular basis is required. Once the girl engages in sexual activity, further natural dilation of the vagina will be achieved.
Surgical alternatives to dilation exist, including the Vechietti procedure. The procedure utilizes traction to create a vagina over the space of a week during inpatient hospitalization. Ongoing dilation is subsequently necessary, either by dilators or by sexual intercourse. Occasionally, a prolapse of the neo-vagina occurs, as the tissues are unsupported. This can be treated surgically with a sacrocolpopexy, attaching the vault of the neo-vagina to the anterior aspect of the sacrum.
Adoption and surrogacy (potentially with donor ovum) are currently the standard methods available to address fertility. Great progress is being made in the field of uterine transplantation. The first baby was born after this procedure in 2014.[13]
As has been discussed, the embryological development of the mesonephric and para-mesonephric ducts occur concurrently; therefore, uterine anomalies commonly coexist with abnormalities of development of the urinary tract. Renal tract anomalies are even more frequently seen in patients with the didelphic uterus congenital anomaly.
The renal anomaly may be a single kidney, or a horseshoe kidney, and the ureters may be duplicated or ectopic, or sometimes blind-ended. Consequently, it is imperative to carry out imaging of the urinary tract when müllerian abnormalities are diagnosed.[14] Figure 33-3 shows an intravenous pyelogram (IVP) of a patient with a single kidney and a müllerian anomaly.
Intravenous pyelogram of the patient with the uterine anomaly seen in Figure 33-2. Note that the absent kidney is on the same side as the obstructed hemivagina.
The hymen is a thin membrane that lies at the embryological junction of the sinovaginal bulb and the urogenital sinus. It usually becomes perforated during fetal life, but may remain imperforate. Although obstruction to menstrual flow has been referred to previously in relation to a blind-ending duplicated vagina, and a noncommunicating uterine horn, an imperforate hymen is the most commonly encountered cause of obstruction to menstrual flow. The incidence of imperforate hymen is 1/1,000 female births.[15] See Figure 33-4 for an image of imperforate hymen/hematocolpos.
Image of imperforate hymen/hematocolpos.
Girls with imperforate hymen usually present with primary amenorrhea, with a history of pelvic pain, which may or may not be cyclical. A palpable pelvic mass due to hematometra may be present.
The patient may present with such severe abdominal pain for which a diagnosis of appendicitis may be considered. When the labia are parted during examination, a bulging bluish membrane is seen. This is sufficient evidence to make the diagnosis. Confirmation is often sought by ultrasound scan.
Treatment is by resection of the hymen under anesthesia, via a cruciate incision, with excision of the hymeneal remnants. Up to two liters of old blood may be released by this procedure. Full recovery without sequelae usually occurs after this procedure. An association between imperforate hymen and endometriosis exists, presumably due to backflow of menstrual fluid through the fallopian tubes.
Far less common than imperforate hymen is transverse vaginal septum, which occurs due to embryological failure of canalization of the müllerian ducts.[16] It presents with the same symptoms, but the characteristic bulging membrane is not seen on inspection. It is of crucial importance to refer the patient to a specialist for appropriate assessment and surgical management. An MRI is required to delineate the septum and to plan the surgical intervention. Induction of amenorrhea should take place with gonadotropin-releasing (GnRH) analogues while investigations are underway.
Transverse vaginal septa may occur anywhere along the length of the vagina; they are classified as upper, mid, and lower. The position will determine the surgical approach, which will be either vaginal or combined abdomino-vaginal. Vaginal dilators will be required to maintain patency of the vagina postoperatively.
Cervical agenesis is even more rare. In the past, hysterectomy was the standard treatment, but recently uterovaginal anastomosis has been performed successfully.
Disorders of sexual development
Disorders of sexual development (DSDs, formerly known as intersex disorders) include complete androgen insensitivity syndrome (CAIS). In this rare X-linked recessive condition, formerly known as testicular feminization, the karyotype is 46XY, but the phenotype is female. The gonads are testes, located in the abdomen or inguinal canals. Testosterone is produced, but the androgen receptors in the end-organ tissues are unresponsive.
In CAIS, during in-utero development, the müllerian structures regress due to normal secretion of the testicular müllerian inhibitory factor. Normal breast development occurs due to peripheral conversion of testosterone to estrogen, and the pubic and axillary hair are generally sparse or absent. CAIS commonly presents with primary amenorrhea, and the vagina is generally found to be short and blind ending.
Partial androgen insensitivity (PAIS) may exist to varying degrees, often presenting at birth as ambiguous genitalia.
In both CAIS and PAIS, sensitive disclosure of the diagnosis to the patient and her family is essential, with the ongoing support of a clinical psychologist. The issue of timing of removal of the gonads must be addressed due to the risk of malignant transformation of the internal testicles.[17]
Congenital adrenal hyperplasia (CAH) is the most common cause of ambiguous genitalia at birth. The majority of cases are due to an enzyme defect known as 21-hydroxylase deficiency. In its most severe form, this can lead to a salt-wasting crisis which is life threatening; therefore, it is imperative to diagnose or exclude this condition as soon as possible after birth.
CAH may occur in either boys or girls. When it affects girls, it brings about masculinization of the external genitalia. Surgical correction entails a vaginal and a clitoral component, and may be carried out in stages, prior to puberty and/or thereafter. A specialist will require careful consideration to determine the type and timing of surgery.
When evaluating the genitalia of a newborn, it is crucial to remember that it is not possible to assign a sex at the time of birth to babies with ambiguous genitalia. A large clitoris and a small penis, with or without hypospadias, may be indistinguishable; genital folds may be either scrotal or labial; and there may be only a single opening on the perineum, which is not clearly urethral or vaginal. Clinical inspection cannot provide a diagnosis, so the clinician must explain the situation to the parents and avoid the temptation to hazard a guess.
Other forms of DSD include Turner syndrome and mixed gonadal dysgenesis.
Turner syndrome has an incidence of 1 in 2,000–3,000 live female births.[16] The classical karyotype is 45X, but many affected girls have mosaic forms such as 45X/46XX or 45X/46XY. The phenotype can vary greatly, and the diagnosis is commonly not made until the girl is in her teens.
Patients with mixed gonadal dysgenesis, which is very rare, generally have female internal genitalia, but with a testis on one side (often in the inguinal ring) and an undifferentiated gonad on the other side.
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