The early history of the neurofibromatosis. Evolution of the concept of neurofibromatosis type 2.

Although neurofibromatosis (NF) became widely recognized as a pathologic entity in the late 19th century, only relatively recently has a clear distinction been made between its generalized form and the central variety. The latter form is typified by bilateral acoustic neuromas (ANs), which may be accompanied by other intracranial tumors, in particular, meningiomas. Up until almost the current era, confusion regarding the protean manifestations of the 2 types of NF existed in the minds of clinicians and in the literature. In 1987, a consensus panel of the National Institutes of Health differentiated the clinical manifestations associated with classic von Recklinghausen syndrome from those of the predominantly intracranial subtype and they were subsequently deemed NF type 1 (NF-1) and NF type 2 (NF-2), respectively. During the last few years, the genetic flaws that underlie these 2 syndromes have been elucidated, revealing that their origins lie in defects on separate chromosomes. The early literature on the subject included repeated descriptions of patients with manifestations typical of NF-2. The investigators, however, considered the intracranial lesions to be merely 1 facet of the generalized form of the disease. A few prescient individuals, however, demonstrated an appreciation for the distinguishing characteristics between these superficially similar, yet quite different, syndromes. The goals of this article are to trace the evolution of the concept of NF-2 as a distinct clinical entity from NF-1 and to assess the early awareness of and attitudes toward bilateral ANs, familial ANs, and ANs associated with other intracranial tumors.