Childhood neurofibromatosis: risk factors for malignant disease.

Forty-five children with both neurofibromatosis and malignant tumors were compared with a pediatric population with neurofibromatosis without tumors to ascertain if any of the clinical manifestations of this disorder were associated with either tumor development or histology. No such factors emerged except that, in most of the optic glioma patients, the neurofibromatosis mutation was paternally inherited. Concordance of histologic tumor types was seen when malignancies occurred in affected family members, similar to that noted in the literature. Although cancer is independent of the other manifestations of neurofibromatosis and these manifestations may vary among family members, it appears that malignant tumors are often concordant when they occur within a family.