IMPE Abstracts

Introduction: CPP is the onset of secondary sexual characteristics before the age of 8 years for girls, due to early activation of the hypothalamic-pituitary-gonadal axis. Near 90% of girls have idiopathic CPP, in rare cases, CPP may occur due to intracranial pathology causing organic CPP. Brain Magnetic Resonance Imaging (B-MRI) with gadolinium is the tool to exclude organic CPP. There is controversy regarding the need for MRI testing in CPP girls whose puberty started at age 6 years or older.

Aims: To determine the frequency and characteristics of lesions detected in girls between 6-8 years old with a diagnosis of presumed Idiopathic CPP by B-MRI with and without gadolinium. To evaluate whether the performance of B-MRI should be maintained as a recommendation in girls in the 6-8 years group developing CPP who are considered presumed idiopathic.

Patients and methods: We performed a retrospective observational cohort study. Data from medical records of patients with a history of presumed idiopathic CPP diagnosed between March 2015 and March 2020 from 4 Argentinian hospitals were included. In all patients, B-MRI was performed with 1.5 T scanners using standard T1 - T2 weighted images, with gadolinium contrast. Inclusion criteria: progressive breast development that begins between 6-8 years, growth velocity > Pc 75, bone age advancement greater than 1 year to chronological age, baseline gonadotrophins: LH ≥ 0. 3 mIU/ml or LH stimulated peak ≥ 6 mIU/ml, physical examination and background for consideration in the classification of idiopathic CPP. Exclusion criteria: history of CNS disease, epilepsy, tumors, infiltrative processes, hydrocephalus, myelomeningocele, severe CNS trauma, and genetic or polymalformative syndromes, other causes of peripheral precocious puberty that progress to CPP secondary.

Results: We evaluated 123 clinical records from 4 Argentinian Hospitals. The mean age at the start of CPP was 7.3 ± 0.6 yrs, and the mean age at diagnosis was 8.2 ± 0.7 yrs. Most girls were in Tanner breast stage 3 and biochemical profiles confirmed CPP. Twelve of 123 CPP girls had abnormal MRI (4 Rathke’s cleft cysts, 2 microadenomas, 2 arachnoidal cysts, 3 intraparenchymal lesions, 1 Pineal cyst). No neoplastic lesions nor other lesions that required intervention were identified over follow-up.

Conclusions: In this cohort of 6–8-year-old girls with presumed Idiopathic CPP we found 10% of anomalies in B-MRI, half of them causally related or questionably related to CPP etiology. The need for brain imaging studies must be reconsidered in this age range.