Evaluation of brain MRI lesions in 381 girls with central precocious puberty

Abstract

Central precocious puberty (CPP) in girls is a diagnosis increasingly made by the Pediatric Endocrinologists worldwide. Although it is most frequently of idiopathic origin, magnetic resonance imaging (MRI) of the brain is recommended to rule out organic lesions causing CPP. However, controversy exists regarding the age limits for routinely performing MRI in girls with CPP. Objective: To evaluate the outcome of brain MRI in girls diagnosed with CPP and its relationship with age and clinical and biochemical parameters. Method: A single-center, study of 381 girls with CPP who had brain imaging performed between 2008-2018. The results of imaging were categorised as Group 1:Normal, Group 2: incidental CNS lesions, Group 3: previously known CNS lesions Group 4: newly identified CNS lesions. Clinical and biochemical features of four groups were compared. Additionally, MRI lesion frequency was determined based on three age categories (<6 y, 6-8, >8 years) Results: MRI findings were abnormal in 73 patients (19%). 18 girls (4.7%) had well known brain pathologies at the time of referral. In the remaining 363 girls with CPP, who had no CNS symptoms, MRI revealed CNS abnormalities in 55 girls. In 34 girls (8.9%) MRI findings were considered as incidental findings, which were not related to the early puberty. Another 21 girls (5.5%) had newly identified MRI abnormalities which were considered to be causally related to CPP. Among these, 19 lesions were non-neoplastic and included arachnoid cysts (6) pineal cysts (4) hydrocephaly (2) Chiari Type2 malformation (1) Dandy-Walker malformation(1) and others (5) not requiring surgical intervention during follow-up. There were only 2 tumoral lesions (0.5%) in the cohort (1 hamartoma and 1 glioma) and they required surgical intervention. These two cases were the youngest of the entire cohort (1.0 and 2.7 years of age respectively) and had the highest baseline LH and Estradiol levels. Otherwise, clinical and biochemical parameters were similar in 4 groups. Newly identified CNS lesions were detected throughout all ages including those above 8 years (Table). Conclusion: Although CNS lesions can be detected throughout all age categories in girls with CPP, only 5.5 % are causally related and most of them do not require intervention. CPP due to neoplastic lesions are detected in younger patients who also had a robust activation of pituitary-gonadal axis.