From 1975 to 1988 seventeen patients with neurofibromatosis type 1 and a disfiguring facial plexiform neurofibroma (FPN) were investigated. The FPN was left-sided in 13 patients. It was orbital/periorbital in 4, lower facial in 7 and involved the whole face in 6 subjects. Neuroimaging (n = 13) revealed a tumor (of optic pathways or basal ganglia) in 8, an ipsilateral middle cranial fossa arachnoid cyst in 2, multiple areas of high signal intensity (in T2-weighted magnetic resonance imaging) in 1, and normal findings in 2 patients. In NF-1 patients with FPN there seems to be a high incidence of intracranial tumors and possibly of arachnoid cysts. Our observation has to be confirmed in a larger patient series.