A 16-year-old girl comes to the office for evaluation of excessive facial hair. The patient has used multiple creams and makeup over the last year but is still embarrassed by the facial hair. She also has had irregular menstrual cycles since menarche at age 12; her last menstrual period was 6 weeks ago. She is an avid runner. Blood pressure is 122/70 mm Hg and pulse is 87/min. BMI is 20 kg/m². Physical examination shows hirsutism. The patient has normal external female genitalia; the rest of the examination is unremarkable. Urine pregnancy test is negative. Laboratory results are as follows: Serum glucose and electrolytes are normal. Which of the following is the most likely diagnosis in this patient?

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11ec25c8_d997_7061_bc81_9b3653a6ebe5_MD0003_00 This patient has nonclassic (late-onset) congenital adrenal hyperplasia (CAH) based on hyperandrogenism and an elevated 17-hydroxyprogesterone (17-OHP) level. The majority of nonclassic CAH is due to a partial deficiency in 21-hydroxylase, which results in impaired conversion of 17-OHP to 11-deoxycortisol. Buildup of 17-OHP is then diverted toward adrenal androgen synthesis, resulting in hyperandrogenism. 21-hydroxylase Girls with nonclassic CAH typically present in adolescence or early adulthood with irregular menses, severe acne, and hirsutism; virilization (eg, clitoromegaly, deepening of the voice) is rare. Since the enzyme deficiency in nonclassic CAH is relatively mild, sufficient glucocorticoids and mineralocorticoids are produced; therefore, patients do not have the salt-wasting seen in classic CAH, and electrolytes and blood pressure remain normal. Diagnosis is confirmed by an exaggerated 17-OHP response on ACTH stimulation test. (Choice A) Androgen-producing adrenal tumors typically present in adulthood with rapidly progressive hirsutism and virilization. Serum DHEAS is markedly elevated with concentrations >700 µg/dL. (Choice B) Cushing syndrome can cause hirsutism due to elevated adrenal androgens. However, this patient has no Cushingoid features such as moon facies, buffalo hump, central obesity, hypertension, or electrolyte abnormalities. 17-OHP levels are usually normal in Cushing syndrome. (Choice C) Ovarian germ cell tumors (eg, embryonal carcinoma, choriocarcinoma) typically present with abdominal ascites, pelvic mass, and pregnancy symptoms (eg, breast tenderness). However, they do not usually cause hirsutism. In addition, these tumors often secrete β-hCG, creating a false-positive pregnancy test. (Choice D) Idiopathic hirsutism is due to excessive conversion of testosterone to dihydrotestosterone in the hair follicles. There is usually a positive family history and normal 17-OHP and androgen levels. (Choice F) Patients with polycystic ovary syndrome have menstrual irregularities and hyperandrogenism; however, 17-OHP is not elevated. (Choice G) Anabolic steroid use for performance enhancement presents with hirsutism, voice deepening, increased muscle bulk, and virilization. However, exogenous androgens would not cause elevated 17-OHP. Educational objective: Nonclassic congenital adrenal hyperplasia is caused by a partial deficiency of 21-hydroxylase and typically presents with hyperandrogenism (eg, irregular menses, hirsutism) and elevated 17-hydroxyprogesterone level. References: Non-classic congenital adrenal hyperplasia. (http://www.ncbi.nlm.nih.gov/pubmed/23632099) Congenital adrenal hyperplasia due to 21 hydroxylase deficiency: from birth to adulthood. (http://www.ncbi.nlm.nih.gov/pubmed/23044877) Congenital adrenal hyperplasia: issues in diagnosis and treatment in children. (http://www.ncbi.nlm.nih.gov/pubmed/24254335)

A 16-Year-Old Girl Comes to the Office for Evaluation of Excessive