Abnormalities of the Female Genital Tract

Overview and Imaging.

The two ovaries are ovoid structures generally located posterior or lateral to the uterus within the mesovarium of the broad ligament ( Fig. 126.1 ). Ovaries may be located anywhere along their embryologic course from the inferior border of the kidney to the broad ligament. Ovaries may be involved in indirect inguinal hernias, 15% of which occur in females. Herniated ovaries can extend as low as the labia ( Fig. 126.2 ), the female equivalent of the scrotum.

Ovarian volume can be estimated using the formula for a modified prolate ellipse: 0.52 × L × W × D. Length (L) and depth (D) usually are measured on a longitudinal (parasagittal) image, and width (W) is measured on a transverse view. In the first three months of life, when maternal hormonal stimulation is greatest, ovarian volumes average 1.06 cm ³ but have a range of normal as high as 3.6 cm ³ . The high end of the range of normal is 2.7 cm ³ for 4- to 12-month-olds and 1.7 cm ³ for 13- to 24-month-olds. The mean ovarian volume reported for children older than 2 years who have not undergone puberty is 1 cm ³ . For menstruating females, the mean ovarian volume typically is 6 to 9.8 cm ³ .

Ultrasound routinely identifies follicles or cysts in most girls of all ages. Cystic structures were noted in 80% of the imaged ovaries of a group of healthy children who were newborn to 2 years old, 72% of a 2- to 6-year-old group, and 68% of a 7- to 10-year-old group ( Fig. 126.3 ). Macrocysts occasionally are seen in all age groups. The ovary is not a quiescent organ in childhood but rather is a dynamic organ undergoing constant internal change.

Overview and Imaging.

The uterus of the newborn has a mean length of 3.5 cm, which decreases to 2.6 to 3 cm by the fourth month of life as maternal hormonal stimulation decreases. On ultrasound examination of a newborn's uterus, it is not uncommon to find either a hypoechoic halo around an echogenic endometrial cavity stripe or endometrial cavity fluid. The typical newborn's uterus is shaped like a spade, with the anteroposterior diameter of the cervix as much as twice that of its fundus ( Fig. 126.4 ). The newborn's cervix is also longer than the fundus. After the first year of life, the typical uterus is tube-shaped and remains that way for several years ( Fig. 126.5 ).

Uterine length increases gradually between 3 and 8 years of age. The mean perimenarchal measurement is 4.3 cm. After puberty and fundal development, the typical pear-shaped uterus measures 5 to 8 cm in length ( Fig. 126.6 ). It is said to descend deeper in the pelvis and no longer maintains the typical neutral position of premenarchal life but instead may be anteverted or retroverted.

Overview.

In females, the Müllerian duct system (MDS) normally develops into the fallopian tubes, uterus, and upper vagina, while the wolffian system involutes. External genital development proceeds along female lines except in the presence of androgens. By 11 weeks, a Y -shaped uterovaginal primordium has developed into the two fallopian tubes and fusion of a large portion of the bilateral MDS into a single uterus and upper vagina. Incomplete septal resorption of the fused bilateral MDS can lead to a septate uterus (which may extend into the cervix and vagina) or an arcuate uterus (generally considered a normal variant). Nonfusion or variably incomplete fusion of the MDS can lead to a wide spectrum of anomalies, including partial or complete absence of the uterus, fallopian tubes, and upper vagina (Mayer-Rokitansky-Küster-Hauser syndrome), uterus didelphys, and bicornuate uterus ( Fig. 126.7 ). The association of uterine and renal anomalies is well established, including “obstructed hemivagina with ipsilateral renal agenesis (OHVIRA),” and when a gynecologic anomaly is present, one should evaluate the kidneys and urinary tract ( e-Fig. 126.8 ) and vice versa. While ultrasound may suggest anomalies of the MDS, postpubertal pelvic MRI is the imaging test of choice for characterization.

Overview.

In a girl with a transverse vaginal septum, the vagina is obliterated by fibrous connective tissue with vascular and muscular elements lined by squamous epithelium. The area of obliteration may be a thin membrane, but more commonly it involves a segment of the vagina (segmental vaginal atresia). The imperforate hymen is a thin membrane that forms at the junction of the caudal end of the MDS and the cranial end of the urogenital sinus. Both a transverse vaginal septum and imperforate hymen may present with an obstructed uterus and vagina.

A distended vagina (colpos) or uterus (metros) is filled with secretions (muco), watery fluid (hydro), or blood (hemato). For example, hematometrocolpos is defined as hemorrhagic material filling a distended vagina and uterus. It is suggested on physical examination by either seeing an interlabial mass or palpating a pelvic mass. Clinical presentation in the teenage years includes amenorrhea (despite normal development of secondary sex characteristics) and cyclic crampy abdominopelvic pains, or a pelvic mass resulting from accumulation of menstrual blood in the proximal vagina (and uterus and tubes). Complete or partial obstructions may occur in association with various MDS anomalies.

Imaging.

Ultrasound images are similar in appearance whether seen in a neonate or a menarchal teenager. The distended vagina appears as a round or tubular cystic mass that usually is midline, often containing internal echoes from accumulated cervical mucus secretions or hemorrhage from sloughing of a hormonally stimulated endometrial lining. The uterus can be identified separately from the vagina by the thick muscular uterine wall, whereas the vaginal wall is thin. Pelvic MRI also can show the obstructed vagina and confirm the presence of blood products ( Fig. 126.9 ).

Treatment.

Vaginal obstruction detected in the neonate or infant is typically immediately corrected. In patients presenting with hematometrocolpos at puberty, the obstruction should be corrected as promptly as possible to avoid endometriosis from reverse spillage of menstrual blood into the peritoneal cavity through the fallopian tubes. Hysterectomy is indicated in patients with vaginal agenesis with a rudimentary uterus and a functional endometrium and in patients with cervical atresia occurring as an isolated lesion or in association with vaginal agenesis (forms of Mayer-Rokitansky-Küster-Hauser syndrome).

Overview and Imaging.

The differential diagnosis of interlabial masses is usually made on visual inspection based on the location and external appearance of the mass. Masses associated with the urethral orifice include prolapse of an ectopic ureterocele (identified as a small, reddened, doughnut-like mass with its central opening being the ureteral meatus itself) and cystic dilatation of an obstructed paraurethral (Skene) gland (presenting as a mass located on either side of a displaced urethral meatus). Masses associated with the vaginal introitus include prolapse of a vaginal cyst (a remnant of the wolffian or Müllerian duct systems or epithelial inclusions originating from elements of the urogenital sinus), an imperforate hymen ( e-Fig. 126.10 ), cystic dilatation of an obstructed Bartholin gland, and prolapse of a sarcoma botryoides (embryonal rhabdomyosarcoma) of the vagina.

A cystogram or vaginogram as well as ultrasound of the bladder and vagina may be necessary to further define the lesion. CT or MRI may help if continued anatomic questions remain. At times, only examination under anesthesia and surgical exploration are conclusive.