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Difficulty: HardMenstrual Cycle Abnormalities and Contraception

A 16-year-old girl is evaluated in the clinic for absence of menarche. She reports no cyclic pelvic or abdominal pain. She has experienced normal growth spurts, and her 14-year-old sister began menstruating a year ago. She takes no medications and has no significant past medical history. Vital signs are within normal limits. On physical examination, height is at the 65th percentile and weight is at the 60th percentile. Breast development is Tanner stage 4, and pubic and axillary hair are Tanner stage 4. Pelvic examination reveals normal female external genitalia and a shortened, 3-cm blind-ending vaginal pouch. Transabdominal ultrasonography reveals the absence of a uterus and cervix, but symmetric, morphologically normal ovaries are visualized. Laboratory evaluation shows a serum testosterone concentration of 40 ng/dL (reference range for females: 15-70 ng/dL). Karyotype analysis reveals a 46,XX chromosomal pattern. Which of the following is the most appropriate next step in the management of this patient?

  1. Renal ultrasonographyAnswer
  2. B
    Bilateral gonadectomy
  3. C
    Measurement of serum 17-hydroxyprogesterone
  4. D
    Dual-energy x-ray absorptiometry scan
  5. E
    Magnetic resonance imaging of the brain

Answer

Renal ultrasonography
This patient presents with primary amenorrhea, normal secondary sexual characteristics, an absent uterus, a 46,XX karyotype, and female-range testosterone levels. This constellation of findings is diagnostic of Müllerian agenesis (Mayer-Rokitansky-Küster-Hauser syndrome). Because the Müllerian (paramesonephric) ducts share a common embryologic origin with the Wolffian (mesonephric) ducts—which ultimately form the renal system—up to 40% of patients with Müllerian agenesis have concomitant urologic anomalies, such as unilateral renal agenesis or a pelvic kidney. Therefore, the most appropriate next step in evaluation is renal ultrasonography. Skeletal anomalies are also common and may warrant further spinal imaging.

Step-by-Step Solution

1
Analyze the primary amenorrhea presentation and physical findings.
The patient has fully developed secondary sexual characteristics (Tanner stage 4 breasts and pubic hair) but an absent uterus and a blind-ending vagina.
This isolates the etiology to a peripheral anatomical defect rather than a central axis failure.
2
Differentiate between the causes of an absent uterus.
Normal female-range testosterone levels, a 46,XX karyotype, and normal pubic hair distinguish this condition as Müllerian agenesis rather than Androgen Insensitivity Syndrome (which features male-range testosterone, a 46,XY karyotype, and absent/sparse pubic hair).
Precise diagnosis is necessary to determine the specific systemic associations and required follow-up.
3
Identify the conditions developmentally associated with Müllerian agenesis.
Because the paramesonephric (Müllerian) and mesonephric (Wolffian) ducts share a close embryologic origin, patients are at high risk for urologic anomalies.
Screening for unilateral renal agenesis, pelvic kidneys, and duplicated collecting systems is mandatory.

Key Concept

Patients diagnosed with Müllerian agenesis (Mayer-Rokitansky-Küster-Hauser syndrome) require prompt evaluation with renal ultrasonography due to a high incidence (30-40%) of concomitant urologic anomalies.
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Topics

Menstrual Cycle Abnormalities and Contraception

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