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We re-examined 21 children with the possible diagnosis of peripheral neurofibromatosis (NF1) based on the presence of cafè-au-lait (CAL) spots as the single clinical finding. We evaluated whether “typical” or “atypical” appearance of the spots was important for the final diagnosis and whether the co-existence of other nonspecific signs (e.g. pectus excavatum) were of any significance for the final diagnosis. In 8/14 (57.1%) cases with “typical” CAL spots, the diagnosis of NF1 was finally established on the basis of other criteria. For the other 6 patients the diagnosis is not yet definitive but highly probable on the basis of the presence of macrocephaly, pectus excavatum and/or MRI findings. Only one patient among five with “atypical” CAL spots possibly has NF1.

We report the results of the reevaluation of 24 patients with neurofibromatosis type 1 (NF1) using central nervous system (CNS) imaging techniques. The first examination by computed tomography (CT) or magnetic resonance imaging (MRI) indicated the presence of optic glioma in three cases, “unidentified bright objects” (UBOs) in six, and a suspected right frontal tumor in one. In two patients optic glioma and UBOs were both present and in one of them a bulbar tumor was also suspected. Later imaging examinations revealed the appearance of optic glioma in three more cases and UBOs in nine. In two of these patients both optic glioma and UBOs were present. This study indicates that the likelihood of detecting imaging abnormalities in patients with NF1 increases when systematic follow-up is performed. Optic gliomas are characteristic of pediatric patients; they rarely give rise to clinical manifestations (1/6 cases) and in general progress very slowly. For these reasons, therapeutic strategy must be carefully considered and individually decided. UBOs are very frequent findings in pediatric patients with NF 1 and therefore they must be considered diagnostically relevant. They are not related to clinical manifestations and spontaneous regression has been observed. The nature of these imaging abnormalities is still unknown, but because they do not behave like tumors, useless and dangerous therapeutic procedures should not be employed.

The von Recklinghausen neurofibromatosis (NF1) gene has been mapped to the pericentromeric region of chromosome 17 and various DNA markers have been identified in this region. We have performed a genetic analysis using an anonymous DNA marker, HHH202 (D17S33), tightly linked to the NF1 gene in seven NF1 Italian families. Only one family was fully informative for the HHH202/RsaI polymorphism. In this family this marker can be used for presymptomatic and prenatal diagnosis. However, it is necessary to use additional flanking markers in order to increase informativeness and to obtain better diagnostic accuracy.