A Case of a Girl with Arnold-Chiari Type 1 Malformation with Precocious Puberty.

A small percentage of individuals have the neurological anomaly of central precocious puberty (CPP). Common neurologic causes of CPP include a tumor or congenital lesions. Although Arnold-Chiari malformation can be caused by congenital or acquired causes, it is unusual in patients with CPP. We present the case of a girl aged 4.5 years who complained of breast budding. Her neurological examination and growth pattern were normal. She had no endocrinological abnormality, except for true precocious puberty. We performed brain magnetic resonance imaging, which showed an Arnold-Chiari type 1 malformation. Currently, this case represents the youngest girl who exhibited both Arnold-Chiari type 1 malformation and precocious puberty. Furthermore, it is likely that there is a meaningful association between the brain lesion and precocious puberty in this case.