An 18-month-old girl presents with unilateral breast budding noticed by her mother for 3 weeks. There is no pubic hair, no growth acceleration, and no vaginal bleeding. Growth chart shows height and weight both at the 50th centile. Bone age is equal to chronological age. The breast bud has not enlarged on follow-up at 6 months. What is the most likely diagnosis?

• A Premature thelarche ✓
• B Central precocious puberty
• C Ovarian granulosa cell tumor
• D Exogenous estrogen exposure

Explanation

Premature thelarche is a benign, self-limited condition characterized by isolated breast development, typically before age 2, without other signs of puberty. Growth velocity and bone age remain normal, unlike central precocious puberty where bone age is advanced and growth is accelerated. Ovarian tumors cause progressive breast development with measurable estrogen levels. Exogenous estrogen exposure would cause bilateral, progressive breast development and withdrawal bleeding upon cessation.

Reference: Nelson Textbook of Pediatrics, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.