Imaging of Intracranial Abnormalities in Neurofibromatosis Types 1 and 2

Abstract

The neurofibromatoses form the largest group of the neurocutaneous disorders. These are autosomal dominant gene disorders characterised by a propensity to dysplasia or neoplasia of the central and peripheral nervous system, skin and eyes. They were first recognised as a pathologic entity in the nineteenth century although case reports of patients with illnesses very much like neurofibromatosis existed in the literature from as early as the 13th century (Mulvihill et al. 1988). Considerable confusion exists in the literature between the two main types of neurofibromatosis and a multitude of terms has been used to describe them. A National Institute of Health consensus development conference enumerated the clinical diagnostic criteria for each of the forms of neurofibromatosis (Tables 18.1, 18.2) and introduced the now widely accepted nomenclature neurofibromatosis 1 (NF1) and neurofibromatosis 2 (NF2) (National Institute Of Health Consensus Development Conference 1987). The recent identification of the NF1 gene and gene product neurofibromin in 1990 and 1991 respectively and the NF2 gene and gene product merlin or schwannomin in 1993 (Martin et al. 1990; Rouleau et al. 1993; Mc Collin et al. 1993) have confirmed the separate nature of these disease processes and enabled accurate distinctions to be made between them (Gutmann et al. 1997). In this chapter we will review the pathological and neuroimaging findings of the two disorders.