The prevalence of precocious puberty and its relationship to optic pathway tumors (OPTs) have been examined in 219 children with neurofibromatosis 1 (NF-1) seen between Jan 1985 and April 1993 at Children’s Memorial Hospital, Chicago. Of seven (3%) with precocious puberty, all had OPTs which involved the optic chiasm and all had abnormal luteinizing hormone-releasing hormone (LH-RH) stimulation tests. They represented 39% of children with NF-1 and chiasmal tumors. Seventy-six percent of OPTs were detected by screening with neuroimaging rather than by clinical symptoms. Biochemical evidence of premature hypothalamic-pituitary-gonadal axis activation may be demonstrated by LH assay, without provocative testing, before overt signs of puberty appear. 
COMMENT. Precocious puberty associated with neoplastic invasion of the hypothalamus has been reported with gliomas, hamartomas, infundibulomas, and supracellar cysts. Ford FR, in his classic textbook, Diseases of the Nervous System in Infancy, Childhood and Adolescence, 4th ed (Springfield Illinois, CC Thomas, 1960), refers to precocious puberty seen occasionally in cases of tuberous sclerosis and von Recklinghausen’s disease. The association with optic pathway tumors and NF-1, emphasized in the present Chicago study, was noted in a 1979 article cited by the authors.