Introduction

Van Wyk-Grumbach syndrome (VWGS) is a rare configuration of endocrine disorders due to long-standing hypothyroidism leading to precocious puberty (PP) symptoms.

Case report

We present a case report of a 7-year-old female patient who was referred due to a vaginal hemorrhage lasting for several days. On physical examination: height was within the 10th–25th percentile, body weight > 97th percentile. She had dry skin, and excessive subcutaneous adipose tissue. Sexual development was at Tanner stage 2. The thyroid gland was non-palpable. Laboratory findings were as follows: TSH > 100 µIU/ml (normal range [N]: 0.7–4.17), fT4 < 0.42 ng/dl (N: 0.7–1.37), fT3 1.38 pg/ml (N: 2.79–4.42), PRL 82.18 ng/ml (N: 5.18–26.53), E2 40 pg/ml (N: < 20), LH < 0.03 mIU/ml (N: 0.03–0.55), FSH 8 mIU/ml (N: 0.7–3.39), positive anti-thyroid antibodies (TPO–Abs and Tg–Abs). Bone age was assessed as 9 years. Thyroid ultrasound (US) showed a characteristic pattern of autoimmune thyroid disease (AITD). Abdominal US showed a multicystic lesion in the right ovary. The patient was diagnosed with AITD, which caused gonadotropin-releasing hormone (GnRH) – independent precocious puberty. Replacement therapy with levothyroxine (LT4) was initiated, which resulted in the gradual normalization of thyroxine and TSH, followed by restoration of other hormonal axes, and eventually cessation of bleeding.

Conclusions

This case presents a rare cause of PP. Hypothyroidism and elevated TSH levels can lead to complex hormonal disturbances affecting the gonadotropin-gonadal axis, including the formation of cystic changes in the ovaries and increased production of E2 and PRL. Thyroid hormone assessment is essential in diagnosing PP.