A 29-year-old woman, gravida 0, seeks medical advice for a 9-month history of secondary am… — USMLE Step 2 CK

A 29-year-old woman, gravida 0, seeks medical advice for a 9-month history of secondary amenorrhea and infertility. During the past 4 months, she has also noted severe cystic acne, increased terminal hair growth on her face and chest, and a noticeable deepening of her voice. She has no history of medical conditions and takes no medications. Her blood pressure is 126/80 mm Hg, pulse is 76/min, and BMI is 24 $kg/m^2$ . Physical examination demonstrates temporal balding, pronounced facial hirsutism, and clitoromegaly. Pelvic examination is limited by patient guarding, and no distinct adnexal masses are palpated. A urine $\beta$ -hCG test is negative. Laboratory evaluation reveals the following:

Total testosterone: 195 $ng/dL$ (normal: 15-70 $ng/dL$ )
Dehydroepiandrosterone sulfate (DHEAS): 210 $\mu g/dL$ (normal: 35-430 $\mu g/dL$ )
Prolactin: 14 $ng/mL$ (normal: 4-23 $ng/mL$ )
Thyroid-stimulating hormone: 2.1 $\mu U/mL$

Which of the following is the most appropriate next step in the evaluation of this patient?

Pelvic ultrasonographyAnswer
B
Computed tomography of the abdomen
C
Measurement of serum 17-hydroxyprogesterone
D
2-hour oral glucose tolerance test
E
Brain magnetic resonance imaging

Answer

Pelvic ultrasonography

The correct answer is pelvic ultrasonography because the patient presents with rapid-onset virilization (clitoromegaly, temporal balding, deepening voice) and significantly elevated serum testosterone with normal DHEAS. This clinical and laboratory profile points directly to an ovarian androgen-secreting tumor (e.g., Sertoli-Leydig cell tumor). The ovaries predominantly secrete testosterone, whereas the adrenal glands secrete DHEAS. Therefore, an isolated elevation in testosterone requires visualization of the ovaries via pelvic ultrasound.

Step-by-Step Solution

Differentiate between simple hyperandrogenism and frank virilization based on the clinical presentation.

The patient exhibits clitoromegaly, temporal balding, and a deepening voice, which are signs of frank virilization rather than simple hyperandrogenism (which typically presents only with acne and hirsutism).

Frank virilization indicates a rapidly progressive, likely neoplastic source of androgens, whereas simple hyperandrogenism suggests a benign functional disorder like PCOS or NCAH.

Interpret the laboratory values to localize the source of the excess androgens.

The total testosterone is markedly elevated (> 150 ng/dL), while the DHEAS level is completely normal.

Testosterone is secreted by both the ovaries and the adrenal glands, but DHEAS is exclusively produced by the adrenal glands. A high testosterone with normal DHEAS localizes the pathology to the ovaries.

Select the appropriate initial imaging modality to investigate the localized pathology.

Pelvic ultrasonography is chosen to image the ovaries.

Pelvic ultrasound is the first-line, standard-of-care imaging test for visualizing the female reproductive tract and evaluating for ovarian neoplasms such as Sertoli-Leydig cell tumors.

Key Concept

Differentiation of androgen-secreting tumors using biochemical markers (Testosterone vs. DHEAS) to guide specific site imaging.

Estimated Time:1m 30s

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