The Müllerian (paramesonephric) ducts develop at 5 to 6 weeks gestational age in conjunction with the Wolffian (mesonephric) ducts. In the absence of “testis-determining factor” of the Y chromosome, the Wolffian ducts degenerate. At 7 to 9 weeks gestational age, the Müllerian ducts fuse at the midline to form the uterovaginal canal. The proximal segments of the uterovaginal canal are derived from coelomic epithelium; these remain unfused and give rise to the fallopian tubes. At approximately 8 weeks gestational age, the uterovaginal canal extends inferiorly to reach the urogenital sinus (vertical fusion). At the same time, the vaginal plate develops in the distal portion of the uterovaginal canal. The vaginal plate subsequently undergoes canalization. Approximately the upper two-thirds of the vagina derive from the Müllerian ducts and the lower one-third develops from the urogenital sinus. The uterus has assumed its mature configuration by 12 weeks gestational age.

In the neonate, the uterus is relatively large due to the influence of maternal and placental hormones. The normal neonatal uterus is approximately 3.5 cm long and 1.4 cm thick, and the fundus-to-cervix ratio (diameter of the fundus divided by the diameter of the cervix) is 1:2. There is shrinkage to prepubertal morphology over the next few months, assuming a tubular configuration (fundus-to-cervix ratio = 1.0), 2.5 to 4 cm in length and less than 1 cm in thickness (Figures 53-1 and 53-2). A uterine length of greater than 4.5 cm and thickness greater than 1 cm in a prepubertal girl suggest pathological enlargement. At the time of puberty, the uterus enlarges to an adult size and configuration, with a fundus-to-cervix ratio of 2:1 to 3:1. The normal postpubertal uterus is 5 to 8 cm long and 1.6 to 3.0 cm wide.^1–5

The endometrial stripe is often visible on sonography and MRI in the neonatal uterus, due to maternal stimulation (Figure 53-3). It is otherwise absent on sonographic imaging of the normal prepubertal uterus; a thin stripe sometimes remains visible on MRI of these older children. At puberty, the normal adult zonal pattern of the endometrium becomes evident on sonography and MRI. On T2-weighted MR, the postpubertal uterus has 3 zones: the intermediate-to-high-signal-intensity outer myometrium, the low-signal-intensity inner myometrium (or junctional zone), and the high-signal-intensity endometrial complex. The double-layer endometrial thickness varies from 2 to 3 mm during the early menstrual phase to approximately 15 mm during the secretory phase.

Most developmental anomalies of the uterus and vagina involve Müllerian agenesis, abnormal/deficient lateral fusion, or abnormal/deficient vertical fusion. Fusion of the Müllerian ducts results in an embryonic uterine septum that normally regresses due to apoptosis; mediation of this process involves the Bcl2 gene. Failure of regression results in a septate uterus. Partial or complete unilateral hypoplasia of the uterovaginal canal results in unicornuate uterus. Uterus didelphys results from complete failure of fusion of the Müllerian ducts. Bicornuate uterus is due to incomplete fusion of the superior segment of the uterovaginal canal. Vaginal and uterine agenesis or hypoplasia results from early failure of paramesonephric duct development. Defects in vertical or lateral Müllerian duct fusion lead to vaginal septa, which can be obstructive. Table 53-1 summarizes a classification scheme for Müllerian duct anomalies that was created by the American Society of Reproductive Medicine as a modification of a system proposed by Buttram and Gibbons in 1979. The prevalence of uterine anomalies in the general population is approximately 0.5%.^6–9

The somatic anlagen of the gonads develop within the paired urogenital ridges in the posterior wall of the coelomic cavity early during embryogenesis. Primordial germ cells migrate from the yolk sac along the mesentery to seed the embryonic gonads. At this stage, the gonad consists of germ cells and supporting epithelial and mesenchymal cells. In males, the presence of testis-determining factor causes the gonad to begin forming testicular elements. When a Y chromosome is not present, the lack of testis-determining factor results in differentiation into an ovary. Germ cell meiosis begins during weeks 10 to 12, eventually resulting in the formation of mature oocytes. Granulosa cells derived from coelomic epithelium form follicles around the oocytes. Mesenchymal cells within the developing ovaries differentiate to produce steroids.

As with the uterus, the normal ovaries of the neonate are slightly prominent due to maternal stimulation. The mean ovarian volume (V = 0.525 × length × width × depth) in infants is approximately 1 cm³. This decreases to 0.7 cm³ during the second year of life. By the age of 5 to 6 years, the volume has increased to 1 cm³. In premenarchal girls, the ovarian volumes are usually in the range of 2 to 4 cm³. The average volume in postmenarchal girls is 8 cm³, with a range of 2.5 to 20 cm³. In general, length and width measurements suggesting abnormal ovarian enlargement are greater than 2.2 × 1.1 cm during the first 5 years of life, and greater than 2.7 × 1.4 cm between 6 years and puberty. The ovaries of postpubertal girls should measure approximately 2.5 to 5.0 × 1.5 to 3.0 cm. Primordial follicles are visible with sonography or MRI in the ovaries in most infants and children. These unstimulated follicles usually measure less than 10 mm in diameter.^1,10–12

Clinical Presentations: Premature Maturation

Several key clinical milestones characterize development of the female genital system. Pubarche refers to the onset of puberty, which is initiated by hormones secreted by the adrenal glands. Menarche is the first episode of vaginal bleeding that originates from the uterus. Initiation of menarche is by secretion of estradiol from the ovaries. The mean age of menarche in North American girls is approximately 13 years. Other hormonally initiated manifestations of sexual development include thelarche (the onset of breast development) and adrenarche (the development of pubic and axillary hair).¹

Sonographic features of hormonal stimulation of the pediatric internal genital system include enlargement of the uterus and ovaries. The uterine fundus enlarges disproportionately to the cervix, such that the fundocervical ratio increases to greater than 2. The thickness and volume of the uterus increase in comparison to those of the prepubertal stage. In addition, the endometrium becomes echogenic. Pelvic sonography is usually normal in girls with isolated premature adrenarche or isolated premature thelarche.

Precocious puberty in girls refers to complete sexual development prior to 8 years of age. There are 2 general types of precocious puberty, central and peripheral. The central form is due to elevated secretion of gonadotropins. About two-thirds of these cases are idiopathic and one-third are due to a demonstrable central nervous system abnormality (e.g., a suprasellar mass). The peripheral form, also termed pseudoprecocious puberty or gonadotropin-independent puberty, is unrelated to gonadotropin hypersecretion. An autonomous ovarian cyst (elevated estradiol secretion) is the most common cause. Peripheral precocious puberty is a component of the McCune-Albright syndrome. An estrogen-secreting neoplasm (e.g., gonadoblastoma) is a rare cause of peripheral precocious puberty.

Sonography of patients with primary precocious puberty frequently (at least 50% of patients) shows enlargement of the ovaries and uterus. Return to normal morphology is the rule with medical therapy.¹³ In many patients with secondary precocious puberty, the examination also demonstrates a unilateral follicular ovarian cyst. The “daughter cyst sign” (the follicle is visualized as a cyst within the lumen of a larger cyst) is common in this situation, which helps to confirm that the cyst is indeed ovarian.^14,15

The differential diagnosis of prepubertal vaginal bleeding includes various considerations in addition to precocious puberty. Trauma and vaginal foreign bodies are important causes in young children. In infants, vascular lesions can present with vaginal bleeding. A vaginal tumor can also cause bleeding.

Vaginal and Uterine Agenesis and Hypoplasia

Congenital absence of the vagina occurs in 1 in 4000 to 1 in 5000 live female births. The most common form of vaginal agenesis is Mayer-Rokitansky-Küster-Hauser syndrome (Müllerian agenesis); this includes skeletal (12% of patients), spinal, and renal (half of patients) anomalies.¹⁶ This syndrome is an important potential cause of primary infertility. The pathogenesis of this condition is bilateral failure of Müllerian duct development. The upper two-thirds of the vagina are absent; 90% of patients also have agenesis of the uterus and fallopian tubes. The ovaries are usually normal. Upper tract anomalies are encountered in approximately one-third of these patients, mostly consisting of renal agenesis, renal ectopia, and renal fusion anomalies.¹⁷ Girls with complete agenesis of the vagina and uterus are asymptomatic aside from primary amenorrhea. Secondary sexual characteristics are normal.^1,18,19

There is an uncommon isolated form of vaginal agenesis, in which there is an obstructed or small rudimentary uterus. This anomaly is due to failure of development of the sinovaginal bulb. Approximately 10% of patients with vaginal atresia have a rudimentary uterus. These patients may present with cyclic pelvic pain at puberty due to the presence of functional endometrium and complete vaginal obstruction.

In most children with vaginal agenesis, sonography and MR show normal ovaries and no visible uterus (Figure 53-4). Occasionally, a small uterine remnant is present. There can be fluid in the remnant, due to hematometra. Lack of vaginal tissue can often be documented in older children with MR; this is best evaluated on axial images. When a uterine remnant is present in patients with vaginal agenesis, the myometrium typically has abnormal low signal intensity on T2-weighted MR images.^19–22

Clinical Presentations: Primary Amenorrhea

The definition of primary amenorrhea is lack of menarche by 16 years of age or lack of menarche more than 3 years after adrenarche and thelarche. Lack of thelarche or adrenarche by 14 years of age is also abnormal. The causes of primary amenorrhea include gonadal dysgenesis (33%), Müllerian anomalies (20%), hypothalamic-pituitary abnormalities (15%), and constitutional disorders (10%).^1,23

Normal menarche occurs between the ages of 9 and 16, with a mean of slightly less than 13 years. Primary amenorrhea occurs in less than 0.1% of girls in the United States. Manifestations of pubarche may or may not be present in these patients. There are myriad causes of primary amenorrhea. Lack of onset of normal menstruation is sometimes the initial clinical manifestation of a genital tract anomaly such as imperforate hymen or agenesis of the uterus or vagina. Gonadal dysgenesis in patients with Turner syndrome is associated with primary amenorrhea. The differential diagnosis also includes intersex conditions, malnutrition, long-term illness, extreme obesity, anorexia nervosa, repetitive strenuous exercise, cystic fibrosis, Cushing disease, thyroid disease, polycystic ovarian disease, hypogonadotropic hypogonadism, congenital heart disease, and tumors of the pituitary, ovary, or adrenal gland.

Unicornuate Uterus

Unicornuate uterus is due to failure of 1 Müllerian duct to elongate while the other develops normally. This accounts for approximately 20% of Müllerian duct anomalies. In 65% of individuals with unicornuate uterus, there is a contralateral rudimentary uterine horn. The rudimentary horn may or may not communicate with the unicornuate uterus. The rudimentary horn may contain endometrium (cavitary) or consist predominantly of fibrous tissue (noncavitary). There is a predominance of unicornuate uterus on the right. Most patients are asymptomatic, although obstetric complications can occur. In those patients with a functional noncommunicating rudimentary horn, dysmenorrhea and hematometra may develop at menarche. Ipsilateral renal anomalies occur in approximately 40% of girls with unicornuate uterus; these include agenesis (about two-thirds of cases), ectopic kidney, horseshoe kidney, and renal dysplasia.

A vaginogram of the infant with unicornuate uterus (or hysterosalpingography in the older patient) shows a small fusiform uterine cavity that is shifted to 1 side and communicates with a single fallopian tube (Figure 53-5). The unicornuate uterus appears small on sonographic examination, and usually deviates to 1 side of the pelvis. Occasionally, a contralateral rudimentary horn is visible, thereby confirming the diagnosis.

Unicornuate uterus has an elongated curved configuration on MR. The endometrium is usually narrow, and sometimes tapers at the apex. MR is useful for the detection and characterization of a rudimentary horn in patients with unicornuate uterus. The MR findings help to determine if the rudimentary horn is communicating versus noncommunicating and cavitary versus noncavitary. A rudimentary horn that has endometrial signal on T2-weighted MR images (the cavitary form) usually requires surgical resection to prevent various potential obstetric and nonobstetric complications such as hematometra. The fibrous tissue of a noncavitary (nonfunctioning) rudimentary horn produces low signal intensity on T2-weighted sequences; endometrial tissue is lacking. Normal uterine tissue has a trilaminar character on T2-weighted MR images: high-signal-intensity endometrium centrally, intermediate-signal-intensity myometrium peripherally, and a thinner low-signal-intensity transitional zone between these layers.^6,21,22,24

Vaginal and Uterine Duplication

Uterus Didelphys

With uterus didelphys, there is nearly complete failure of fusion of the Müllerian ducts. Each duct forms a separate hemiuterus and cervix; there is no communication between the endometrial cavities. About three-fourths of these patients have a coexistent longitudinal vaginal septum. In some patients, there is also a transverse vaginal septum that leads to hydrometrocolpos, often unilateral. Most patients with uterus didelphys are asymptomatic, unless there is an obstructing vaginal septum. Uterus didelphys accounts for approximately 5% of uterine developmental anomalies.²⁵

Contrast studies of uterus didelphys show 2 uterine cavities, usually symmetric. When there is an associated longitudinal septum, there are 2 hemivaginas, each of which communicates with an ipsilateral uterine cavity (Figure 53-6). If there is an obstructed hemivagina, vaginography opacifies only 1 hemivagina and uterine cavity; this appearance is similar to that of unicornuate uterus (Figure 53-5). Sonography of uterus didelphys shows completely separate uterine horns and a large fundal cleft (Figure 53-7). There is no visible communication between the endometrial cavities. When there is an obstructing vaginal septum, the hemivagina and 1 or both uterine horns may be distended with fluid. Similar findings can be demonstrated with MR. The uterine horns are divergent and there is a deep fundal cleft. In mature patients, cervical duplication can also be identified on MR.²²

Bicornuate Uterus

A bicornuate uterus consists of 2 symmetric cornua that are fused inferiorly. The endometrial cavities communicate, usually at the uterine isthmus. A bicornuate uterus can be complete or incomplete; the cleft of a complete bicornuate uterus extends to the internal cervical os, and there is usually duplication of the cervix. A partial bicornuate uterus has an external uterine fundal cleft; this cleft is absent or shallow in septate uterus. The distinction between bicornuate and septate morphology is crucial, as there are important differences in prognosis and treatment.

Sonography of bicornuate uterus shows a large fundal cleft and separation of the uterine horns. There are 2 echogenic endometrial complexes (Figure 53-8). The fundal cleft of a bicornuate uterus can also be demonstrated with MR. In teenage and adult patients, the cleft of a true bicornuate uterus should measure at least 1 cm along the external fundal uterine contour. There is myometrial tissue between the 2 uterine horns; this finding can also occur with septate uterus, and is therefore not a useful feature for differentiating between these 2 conditions. A bicornuate uterus has a concave or heart-shaped external contour, whereas a septate uterus usually has a convex or flat external contour.^22,26,27

Septate Uterus

Septate uterus is the most common clinically significant Müllerian duct anomaly, accounting for approximately 55% of uterine anomalies. It is due to partial or complete failure of resorption of the uterovaginal septum after fusion of the paramesonephric ducts. This anomaly is associated with reproductive abnormalities, including spontaneous abortions and premature deliveries. The midline septum in this anomaly is considered to be complete when it extends to the external cervical os. Rarely, complete duplication of the cervix occurs in association with septate uterus. In contradistinction to bicornuate uterus, there is no fundal cleft; accurate differentiation between septate uterus and bicornuate uterus is essential for proper clinical management.^25,28

Sonography of septate uterus shows myometrium of intermediate echogenicity separating the echogenic endometrial cavities at the fundus. The fibrous inferior segment of a complete septum is hypoechoic. With MR, the overall size of the septate uterus is usually normal. The 2 endometrial cavities are smaller than normal. The signal intensity of the fundal segment of the septum is isointense with the adjacent myometrium. With a complete septum, a low-signal-intensity fibrous band extends inferiorly (Figure 53-9). Careful assessment of the external fundal contour is essential for accurate differentiation from bicornuate uterus. With septate uterus, the fundal contour is convex or flat. Occasionally, there is a shallow (<1 cm) cleft. Bicornuate uterus invariably has a deep fundal cleft.^6,22

Arcuate Uterus

Arcuate uterus is a common mild deformity that may represent a normal variation or a mild form of bicornuate or septate uterus. Imaging studies demonstrate a mild indentation of the uterine fundus (<1 cm) and a normal endometrial cavity. Arcuate uterus is of no clinical significance.

Vaginal and Uterine Obstruction

Defective vertical fusion can result in a transverse vaginal septum anywhere along the vagina. These septa most frequently are located at the junction of the upper and middle thirds of the vagina. The membrane consists of fibrous tissue as well as vascular and muscular components. The resultant obstruction causes hydrometrocolpos and, at the time of puberty, hematometrocolpos. With a low septum, dilation may predominate in the distensible vagina and be absent or less pronounced in the more muscular uterus. Imperforate hymen and a low transverse septum have similar appearances on imaging studies, that is, distention of the vagina with fluid (hydrocolpos). Distal vaginal obstruction in the fetus and neonate can cause mucocolpos. Imperforate hymen is a membrane at the level of the introitus that results from failure of the sinovaginal bulbs to canalize. Unlike most other forms of congenital vaginal obstruction, imperforate hymen is not a Müllerian anomaly. Hydrometros without accompanying hydrocolpos raises the possibility of vaginal agenesis or hypoplasia of the cervix. Hydrocolpos and hydrometrocolpos are sometimes associated with other malformations, such as postaxial polydactyly, anal atresia, esophageal atresia, renal agenesis, additional genital anomalies, urogenital sinus, cloacal malformation, and cardiac lesions.^29,30

Sonographic evaluation demonstrates hydrometrocolpos as a pear-shaped cystic mass in the pelvis, with the larger portion directed superiorly. In prepubertal children, the myometrial wall is quite thin. The contents of the cyst usually appear anechoic or hypoechoic in young children; debris is often visible in the fluid in symptomatic pubertal patients. With cervical agenesis, there is tapering of the inferior aspect of the uterine cavity, resulting in a funnel shape. In some patients, particularly pubertal girls with imperforate hymen, the dilation predominantly involves the vagina, that is, hydrocolpos or hematocolpos (Figure 53-10). Mucocolpos in an infant with imperforate hymen or distal vaginal septum is moderately echogenic on sonography.

Hydrometros and hydrocolpos can also be evaluated with MR. The walls of the distended vagina are quite thin, whereas the myometrium has a thicker wall. The fluid within the distended uterus/vagina is hyperintense on T2-weighted images. When present, blood products within the cyst result in elevation of signal intensity on T1-weighted images (Figure 53-11).^21,22,31

Cloacal Malformation

Cloacal malformation refers to an anomaly that occurs exclusively in females, in which the urethra, vagina, and rectum merge distally to form a common terminal channel, the cloaca (Latin for drain). This lesion is distinct from cloacal exstrophy, which is a subtype of bladder exstrophy. With cloacal malformation, the cloaca forms the only perineal opening, and serves as the only outlet for urine, feces, and genital secretions. This anomaly occurs in approximately 2 per 100,000 newborns. Clinical examination shows findings of imperforate anus and a single perineal opening that may have the appearance of a relatively normal urethra or vagina; therefore, a high index of suspicion for this anomaly is essential when evaluating female infants with imperforate anus. The site of insertion of the rectum varies between patients; most common is an opening into the vagina or directly into the cloaca.³²

Additional anomalies are common in patients with cloacal malformation. About half of these patients have a duplication anomaly of the uterus and vagina. About one-quarter have genital tract obstruction that leads to hydrometrocolpos. Potential associated urinary tract pathology in children with cloacal malformation includes vesicoureteral reflux, bladder diverticula, duplication of the bladder or urethra, unilateral renal agenesis, ectopic kidney, renal fusion anomalies, and ureteral obstruction. Sacral hypoplasia or agenesis occurs in approximately 30% of patients with cloacal malformation. There is an increased prevalence of spinal dysraphism and spinal cord anomalies such as tethered cord.³³ An abnormally widened symphysis pubis is present in up to 20% of individuals with cloacal malformation. Less common developmental abnormalities that can occur in other organ systems in association with cloacal malformation include anomalies of the extremities, vertebral lesions, esophageal atresia, intestinal atresia, Meckel diverticulum, ventricular septal defect, tetralogy of Fallot, and craniofacial anomalies. Meconium peritonitis can occur due to spillage of meconium into the peritoneal cavity via the fallopian tubes.³⁴

Although cloacal malformation is too small to be directly visualized in prenatal sonography, a clue to the diagnosis is visualization of calcified meconium in the colon and urinary tract. Other potential findings include fetal ascites, a cystic mass posterior to the bladder, ambiguous genitalia, nonvisualization of the bladder, and oligohydramnios.^35,36 Standard abdominal radiographs of the infant with cloacal malformation may show calcifications due to meconium peritonitis. In some patients, a pelvic mass is visible due to hydrocolpos or hydrometrocolpos; communication with the rectum sometimes results in filling of the distended genital structures with gas. Radiographs show widening of the symphysis pubis in some patients with cloacal malformation.

The most useful study for accurately defining the pathological anatomy in infants with cloacal malformation is genitography. Water-soluble contrast material is introduced via the opening of the cloaca with the infant in the lateral position. Optimally, this allows visualization of the rectum, vagina, and bladder. Manipulation of the catheter may be required to achieve contrast opacification of all of the structures. Contrast can also be injected into the distal colon if a colostomy has been performed. The distended vagina can usually be differentiated from the bladder by noting the rounded filling defect in the dome that represents the cervix. At some point during the examination, frontal images should be obtained to evaluate for bladder or vaginal duplication.

Sonography may be helpful for further defining the anatomy of the bladder, vagina, and uterus in infants with cloacal malformation. The upper urinary tract should also be evaluated for associated anomalies or signs of urinary tract obstruction. Because of the potential for tethered cord and other spinal anomalies, spinal evaluation with sonography or MR is indicated.

Fused Labia

Labial fusion can be congenital or acquired. Most instances of congenital fusion are discovered during routine examination during the perinatal period. Acquired labial fusion or cases of unrecognized congenital fusion may not present until later in childhood, with urinary tract infection, dysuria, or enuresis. In some of these patients, the fused labia cause retention of urine in the vagina during voiding, with subsequent dribbling. Because these symptoms do not necessarily prompt a careful genital examination by the primary care physician, the diagnosis may first be established at the time of attempted catheterization for cystography. Successful catheterization, and mitigation of the symptoms, can usually be achieved by digital separation of the labia after placement of topical anesthetic. Topical steroid cream therapy is also useful for selected patients.³⁷

Gartner Duct Cyst

In normal female embryos, the Wolffian ducts regresses. Small proximal portions persist to receive the tubules of the epoophoron. Remnants of the mid and distal portions of the Wolffian ducts form the Gartner ducts. A Gartner duct cyst, therefore, can be located in the cervix or the wall of the vagina, or within the broad ligament. It can occur in association with ipsilateral renal dysgenesis and/or ipsilateral Müllerian duct obstruction (vaginal septum). Gartner duct cyst can also be associated with an ectopic ureter that opens into the vagina. Occasionally, an ectopic ureter opens into a Gartner duct, without an associated cyst.

Detection of a Gartner duct cyst is possible with sonography, MR, or CT. The cyst can be round, oval, or tubular. Most are paravaginal and in an anterolateral location. The imaging character of the cyst contents varies between patients due to differences in the amount of proteinaceous material within the cavity. In particular, T1-weighted MR images usually show the lesion to be relatively hyperintense. When occurring in association with renal dysgenesis and Müllerian duct obstruction, about half of these cysts are located posterior to the bladder and half protrude into the bladder. The latter presentation frequently mimics a ureterocele. When imaging studies demonstrate an apparent ureterocele or pelvic cyst that is ipsilateral to a dysplastic kidney, the diagnosis of Gartner duct cyst should be considered. Appropriate recognition of these associated anomalies may facilitate an early diagnosis of Müllerian duct obstruction.^38–42

Hydrocele of the Canal of Nuck

Hydrocele of the canal of Nuck is a rare condition that presents as painless swelling in the inguinal region and/or labia majora. The canal of Nuck is the remnant of the processes vaginalis, which is a small evagination of the parietal peritoneum at the site of extension of the round ligament into the inguinal canal. Normally, the canal of Nuck completely obliterates during late fetal life or during the first several months of infancy. Enlargement or persistence results in either an indirect inguinal hernia or a hydrocele. The typical imaging appearance is that of oval or tubular cyst in the inguinal canal or labia majora (Figure 53-12).^43,44

Congenital Inguinal Hernia

An inguinal hernia in a female infant or young girl is often due to persistence of the canal of Nuck. Any of the abdominal or pelvic organs can extend into the hernial sac. In girls, the fallopian tubes, ovaries, uterus, or an ovarian cyst can form the sliding component of an inguinal hernia. Extension of an ovary into an inguinal hernia is the likely diagnosis when there is a moveable mass in the labia majora of an infant female. A fallopian tube or the uterus can accompany the ovary. Usually, the mass is otherwise asymptomatic. However, the elongated pedicle of an ovary trapped in an inguinal hernia makes it prone to torsion. Sonography serves to confirm the presence of an ovary within the hernia and to assess the perfusion status (Figure 53-13). In the absence of torsion, color Doppler demonstrates vessels coursing through the elongated ovarian pedicle (Figure 53-14).^45,46

Pelvic Varices

Abnormal dilation of parauterine and ovarian veins is usually a developmental lesion that has similar pathophysiology as varicocele in males. Some patients have manifestations of nutcracker syndrome, with narrowing of the left renal vein as it crosses the aorta and dilation of the vein proximally. Secondary varices occasionally occur in association with a pelvic mass. Primary pelvic varices can cause pelvic pain syndrome (pelvic congestion syndrome). The typical symptoms are chronic or recurrent dull aching pain in the lower abdomen, pelvis, or lower back. The pain often worsens after prolonged standing.⁴⁷

Imaging studies show pelvic varices as dilation and tortuosity of parauterine and ovarian veins. Concomitant varicosities of the paravaginal and internal iliac veins can occur. As with male varicocele, the left ovarian vein is dilated in some women and girls with pelvic varices. Dynamic contrast-enhanced CT or MR sometimes demonstrates early enhancement of the ovarian vein due to retrograde flow (Figure 53-15). Flow dynamics of the ovarian vein can also be assessed with color Doppler sonography. Standard pelvic sonography with the patient recumbent often fails to demonstrate the abnormal venous dilation. Imaging with the patient upright and/or during the Valsalva maneuver can be helpful in inducing pelvic vein distention.^48,49

Tuboovarian Torsion

Tuboovarian (adnexal) torsion refers to twisting of the ovarian vascular pedicle. Torsion can involve the ovary, the adnexa, or both. This initially results in obstruction of lymphatic and venous drainage. Loss of arterial perfusion may or may not occur. The pathological consequences include congestion, edema, and necrosis. An adnexal cyst or mass can predispose to tuboovarian torsion; however, there is no demonstrated predisposing factor in a substantial minority of children with torsion. Only approximately 10% of postpubertal girls with torsion have an underlying lesion such as a large ovarian cyst or cystic teratoma. Tuboovarian torsion can occur in the fetus; prenatal sonography may demonstrate a cystic area posterior to the bladder, with a fluid–fluid level. The most common cause of tuboovarian torsion in the fetus or neonate is an underlying ovarian cyst. Developmental abnormalities of the fallopian tubes or mesosalpinx can also predispose to this complication.^50,51