A Case of Peripheral Precocious Puberty May Be Caused by a Diet Containing Phytosterols in a 20-Month-Old Boy.

Introduction: Precocious puberty in boys generally remains an etiology. In addition to the causes of endogenous hormone changes, endocrine-disrupting chemicals of exogenous substances may interfere with children's pubertal development.

Case Presentation: A 20-month-old boy presented with peripheral precocious puberty may be due to a phytosterol-containing diet. The patient came to see a doctor because of acne, hairiness, increased penis size, and coarse voice. Genital examination revealed a Tanner stage of 2 for pubic hair and a stretched penile length of 5 cm, which disagreed with the prepubertal testicular volume (2 mL bilaterally). At the same time, he was found to have pigmentation on both nipples and areola. The concentrations of estradiol and testosterone increased significantly. Since the age of 6 months, the patient had taken food added with a large amount of chicken essence seasoning (a flavoring in Chinese cooking), with an average of 15 g of this seasoning a day. A kind of phytosterol (C29H48O) was detected in chicken essence seasoning by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS). After avoidance of the chicken essence seasoning, the patient's sex hormone levels decreased, all clinical symptoms returned to normal, and no further development of secondary sexual characteristics was detected.

Conclusion: This phytosterol-containing diet may be responsible for the sexual development of this patient. However, the mechanism of how phytosterols affect the process of development in children needs to be further explored.