A 26-year-old woman comes to the office due to an 8-month history of an inability to conce… — USMLE Step 2 CK

A 26-year-old woman comes to the office due to an 8-month history of an inability to conceive and absent menses. Menarche occurred at age 13, and her menses were previously regular, occurring every 28 days. Over the past 6 months, she has noticed increased hair growth on her face and chest, severe acne, and a deepening of her voice. She and her husband have been having unprotected intercourse regularly for the past year. She has no significant past medical history and takes no medications. Vital signs are temperature $37.1 \ ^\circ\text{C} \ (98.8 \ ^\circ\text{F})$ , blood pressure $118/74 \text{ mmHg}$ , pulse $78\text{/min}$ , and respirations $16\text{/min}$ . BMI is $24 \text{ kg/m}^2$ . Physical examination reveals moderate acne on the cheeks and jawline, as well as coarse, dark terminal hair on the upper lip, chin, and periareolar areas. Pelvic examination reveals clitoromegaly. Bimanual examination shows a normal-sized uterus, but is otherwise limited due to patient guarding. A urine pregnancy test is negative. Laboratory studies show a serum thyroid-stimulating hormone (TSH) level of $1.9 \ \mu\text{U/mL}$ and a serum prolactin level of $11 \text{ ng/mL}$ . Which of the following is the most appropriate next step in evaluation?

A
Measurement of early morning 17-hydroxyprogesterone level
Measurement of serum testosterone and dehydroepiandrosterone sulfate levelsAnswer
C
Transvaginal ultrasound to assess for polycystic ovaries
D
Initiation of combined oral contraceptive pills
E
Initiation of levothyroxine therapy

Answer

Measurement of serum testosterone and dehydroepiandrosterone sulfate levels

The correct answer is measurement of serum testosterone and dehydroepiandrosterone sulfate (DHEAS) levels. This patient presents with rapid-onset hirsutism, secondary amenorrhea, and frank virilization (deepening voice, clitoromegaly) over a 6-month period. While gradual-onset hyperandrogenism with irregular menses is typical of functional disorders such as polycystic ovary syndrome (PCOS) or non-classic congenital adrenal hyperplasia (NCCAH), the rapid progression and severity of this patient's signs strongly suggest an androgen-secreting tumor of either ovarian or adrenal origin. The most appropriate initial step in evaluation is to measure serum testosterone and DHEAS levels to differentiate the source of the excess androgens. Markedly elevated testosterone typically points to an ovarian source (e.g., Sertoli-Leydig cell tumor), whereas markedly elevated DHEAS points to an adrenal source (e.g., adrenal adenoma or carcinoma).

Step-by-Step Solution

Identify the key clinical features in the patient's presentation.

The patient has secondary amenorrhea, severe rapid-onset hirsutism, and signs of frank virilization (clitoromegaly, deepening of voice) occurring over 6 months.

Recognizing the severity and pace of symptom onset is crucial for differentiating benign functional causes from malignant neoplastic ones.

Determine the most likely underlying pathophysiological process.

Rapid-onset virilization points toward an androgen-secreting tumor rather than a functional disorder like Polycystic Ovary Syndrome (PCOS).

PCOS and non-classic congenital adrenal hyperplasia (NCCAH) typically present with a slow, gradual onset of mild to moderate hyperandrogenism, whereas tumors present rapidly and severely.

Select the appropriate diagnostic test to confirm the source of hyperandrogenism.

Measurement of serum testosterone and dehydroepiandrosterone sulfate (DHEAS) levels is indicated.

Testosterone is primarily secreted by the ovaries, while DHEAS is primarily secreted by the adrenal glands. Elevated levels will localize the tumor source.

Key Concept

Evaluation of rapid-onset virilization and hyperandrogenism

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