Central precocious puberty due to hypothalamic hamartoma in neurofibromatosis type 1

In neurofibromatosis type 1 (NF1), Central Precocious Puberty (CPP) occurs almost invariably in association with optic pathway tumors, usually pilocytic astrocytoma. However, at times aetiology remains undefined. On the other hand, in the general population CPP develops due to an underlying hypothalamic hamartoma in up to 10% of patients. Herein we report on a diagnosis of CPP related to hypothalamic hamartoma in a young girl with NF1 explored with conventional 3-T MRI and quantitative spectroscopy. Our observation suggests that CPP can be due to a tuber cinereum hamartoma also in NF1, with diagnostic, prognostic and therapeutic implications that appear analogous to hamartoma-related CPP in the general population. Conversely the admittedly rare possibility of NF1 has to be entertained in every new diagnosis of hamartoma-related CPP.