Vascular neurofibromatosis affecting the internal carotid artery: a case report

Sella turcica measurements on lateral cephalograms of patients with neurofibromatosis type 1

The aim of this study was to measure line segments and areas of sella turcica on lateral cephalograms with respect to the clinical diagnosis of facial phenotype of patients with neurofibromatosis type 1 (NF1). Special attention was given to correlate the measured values with certain tumour types that are typical for this disease.

Material and methods: Lateral cephalograms of 194 individuals were investigated. Patients with NF1 were further divided according to the detection and topography of facial plexiform neurofibromas (PNF) taking into account the distribution pattern of the trigeminal nerve. All patients with PNF showed unilateral tumour localisation. Patients without any facial PNF constituted a separate group. Healthy volunteers with ideal occlusion and no history of any intervention in the maxillofacial region served as a control group. The following items were determined on the radiographs: sella entrance, sella width, sella depths, sella diagonal, and sella area.

Results: Patients with PNF of the first and second trigeminal nerve branch or affected in all branches showed highly statistically significant enlarged sella tucica measurement values. On the other hand, patients with PNF restricted to one branch only or simultaneously in the second and third branches showed measurement values that were not different to those obtained in NF1 patients devoid of facial PNF. The latter group also showed no difference of sella turcica parameters obtained in the control group.

Conclusion: This study provides evidence for the association of a certain NF1 phenotype with distinct skeletal alterations of the skull base, shown here using the example of the representation of the sella turcica in the lateral radiograph. These findings are also relevant in the discussion of NF1 as a disease of bones and in the assessment of brain development in NF1. Both items are discussed in relationship to a facial plexiform neurofibroma. Furthermore, the knowledge of this association of findings provides the clinician with relevant information in the planning of skull base procedures in these patients.

Hypoplastic Internal Carotid Artery Co-Presenting with Neurofibromatosis and Intracranial Masses

Neurofibromatosis type 1 (NF1) is associated with systemic vascular disease, and it can also affect intracranial vasculature in a small percentage of patients. Very rarely, NF1 may co-present with hypoplasia of the internal carotid artery (ICA). Prior reports have documented NF1 with bilateral optic gliomas and a unilateral hypoplastic internal carotid artery; however, we report a case with the aforementioned findings in addition to a right-sided lentiform mass. This case report further suggests a common congenital pathway related to neurofibromin loss of function resulting in both nerve sheath tumors and cerebrovascular anomalies.

Neuroimaging findings in neurofibromatosis type 1 and 2

Neuroimaging, particularly MR imaging, plays an important role in the diagnosis and management of the patient with neurofibromatosis type 1 and 2. These phakomatoses are complex disorders affecting multiple cell types and multiple systems of the body with a wide range of expression. This article summarizes the neuroradiologic central nervous system findings in these neurocutaneous disorders.

A practice pathway for the initial diagnostic evaluation of isolated sixth cranial nerve palsies

PURPOSE

To define a practice pathway for the evaluation of sixth-nerve palsies (SNPs) and to determine its cost-effectiveness and validity in a retrospective chart review.

METHODS

A Medline search of the English-language literature from 1966 to 1995 was performed to define the available clinical evidence and develop the practice pathway. The authors retrospectively reviewed 407 charts with the diagnosis of SNP seen at three centers. Information obtained included: etiologic diagnosis if known; development of new neurologic or ophthalmologic findings; and results and costs of neuroimaging studies, if performed.

RESULTS

Of the 407 patients, 98 underwent computed tomography scans and 212 underwent magnetic resonance imaging of the head. Eighty cases were non-isolated, 317 were isolated SNP, and ten could not be classified from chart information. Of the 317 cases of isolated SNP, 49 were classified as traumatic; 5, congenital; 158, vasculopathic; 63, nonvasculopathic; and 42, progressive or unresolved. Following the recommendations of the practice pathway, the 158 patients classified as having vasculopathic SNP would not have undergone neuroimaging studies, realizing a savings of $100,000 in this study population of 407 patients.

CONCLUSION

The recommendations of the practice pathway are supported by review of the literature and the retrospective review of these cases. However, a prospective study with a matched control group is needed to demonstrate regional and specialty-specific variations in care and to strengthen the clinical certainty of the pathway recommendations.