A lateral cephalometry study of patients with neurofibromatosis type 1.

PURPOSE: Neurofibromatosis type 1 (NF1) is an autosomal dominant transmitted tumour suppressor syndrome and also a bone disease. Osseous dysplasia affecting the craniofacial region is characteristic of NF1. The aim of this study was to analyse the lateral cephalograms of NF1 patients in comparison to individuals who were not affected by this condition in order to describe the skeletal phenotype of NF1 in more detail. MATERIALS AND METHODS: The study comprises the lateral cephalograms of 172 patients with established NF1 diagnoses (female = 85, male = 87). NF1 patients were distinguished by radiological and/or histological findings of the facial region suggestive of plexiform neurofibroma (PNF) or disseminated cutaneous NF (DNF). The analysed radiographs of a collection of 29 healthy volunteers with ideal occlusion served as controls. The focus of this analysis was cephalometrically defined angles. RESULTS: Cephalometric analyses of patients with DNF did not differ from those of controls for the vast majority of parameters. However, the measurement results of patients with PNF differed significantly from those of healthy volunteers and patients with DNF. The number of trigeminal nerve branches affected in PNF patients had an effect on the measurement results. CONCLUSION: Lateral cephalograms revealed no significant alteration of the facial skeleton in NF1 patients as compared to controls. Indeed, the stigma of a so-called 'NF1 facies' cannot be derived from the cephalometric findings presented. Notably, a wide range of deviating readings were recorded for individuals with facial PNF. Clinicians who treat patients with NF1 should be aware of deviations from cephalometric standards on lateral cephalograms in NF1 patients, especially when craniofacial surgical procedures are planned. Some of these findings, particularly asymmetries of the facial skeleton, could be indicators of an associated PNF.

Analysis of orbital plain radiographs for orbital deformities in neurofibromatosis type 1 patients, with special reference to alterations of the orbital rim as indicators of adjacent plexiform neurofibroma.

UNLABELLED: Neurofibromatosis type 1 (NF1) is an autosomal dominant inherited disease. Some stigmata of NF1 occur in the orbital region. The aim of this study was to reveal whether alterations of the orbital rim visible on plain radiographs may indicate the presence of a plexiform neurofibroma (PNF), a tumour almost exclusively diagnosed in NF1. MATERIAL AND METHODS: The plain orbital radiographs of 73 patients with NF1 (female: N=37, male: N=36) were investigated for alterations of the orbit. The group was further distinguished according to the presence of orbital PNF (N=53) and/or sphenoid wing dysplasia (N=30). Radiographs from patients with NF1 and with exclusion of PNF in the orbitofacial region were used for comparison (N=20). A special cephalometric analysis (Dental Vision™) was adapted to the demands of this study. RESULTS: Patients with NF1 not affected by an orbitofacial PNF exhibited symmetrical orbits. Unilateral increase in orbital height was associated with ipsilateral PNF. The width of orbits affected by a PNF was often slightly increased compared to the non-affected side. The determination of cephalometrically-defined angles disclosed an erection of the PNF-affected orbit compared to the medio-sagittal plane. CONCLUSION: Plain radiographs are often the first diagnostic measure used to determine skeletal alterations. This study shows that certain parameters of the orbital rim are useful indicators of a PNF in patients who are unilaterally affected by this lesion in the orbital or orbitotemporal region.