5 Key Takeaways

• 1

  A girl with estrogen-related changes beginning at 4 months had recurrent vaginal bleeding, advanced bone age, severe anemia, and endometrial abnormalities by age 6 years and 7 months.

• 2

  Whole-exome sequencing identified a likely pathogenic ESR1 p.Tyr537Ser variant, while suppressed luteinizing hormone argued against central precocious puberty; causation remains unconfirmed.

• 3

  Tamoxifen temporarily reduced the cervicovaginal mass and improved symptoms, but recurrence was documented by February 2025, prompting combined letrozole–tamoxifen therapy.

• 4

  The case report authors noted that the long-term malignancy risk is unknown, and the unusually early puberty’s relationship to excessive estrogen receptor activity remains uncertain.

• 5

  The report described atypical endometrial hyperplasia/endometrioid intraepithelial neoplasia in a child, an extraordinarily unusual finding in childhood.