A 4-year-old girl presents with vaginal bleeding, breast development (Tanner stage III), and pubic hair (Tanner stage II). Multiple hyperpigmented macules with irregular, ragged borders are noted over the left buttock and lower back. Bone age is 7 years. GnRH stimulation test shows suppressed LH response (<5 IU/L) with elevated estradiol. What is the most likely diagnosis?

• A Central precocious puberty due to hypothalamic hamartoma
• B Congenital adrenal hyperplasia due to 21-hydroxylase deficiency
• C Primary hypothyroidism
• D McCune-Albright syndrome ✓

Explanation

McCune-Albright syndrome classically presents with the triad of precocious puberty (peripheral, GnRH-independent), café-au-lait spots with irregular 'coast of Maine' borders, and polyostotic fibrous dysplasia. The suppressed LH response to GnRH stimulation confirms peripheral (gonadotropin-independent) precocious puberty. CAH would show virilization with elevated 17-OH progesterone. Central precocious puberty would show a pubertal LH response. Hypothyroidism causes a suppressed LH response but lacks café-au-lait spots.

Reference: Williams Textbook of Endocrinology, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.