Relation of Multiple Neurogenic Tumors in the Spinal Canal to Neurofibromatosis

Objective : The authors characterize a syndrome of multiple neurogenic tumors in the spinal canal, which is unclassifiable by the current National Institute of Health[NIH] criteria for neurofibromatosis. Methods : We retrospectively examined cases in which two or more spinal neurogenic tumors were detected by magnetic resonance[MR] imaging and which had been pathologically confirmed. Eighteen patients were recruited between February 1986 and March 2002. According to NIH criteria, eight cases were neurofibromatosis type 1[NF1], four were type 2[NF2], and six were neither type 1 nor type 2 [Unclassifiable : UC]. The locations of lesions, clinical presentations, radiological findings, and pathological results with immunohistochemistry were reviewed. Results : In the case of NF2, three of four cases were intradural tumors. Pathological examinations revealed neurilemmomas in two of four NF2 and all of the UC cases. In the case of NF1, pathological examinations showed seven neurofibromas and one neurilemmoma. Concerning UC, the age at presentation was middle-aged to late [mean age 48.5, range 35 to 64], which contrasted with ordinary NF2, where patients tended to become symptomatic before 20years of age. The pathological examinations of UC cases revealed neurilemmoma similar to most of NF2 and the immunohistochemical study showed characteristic of NF1. Conclusion : Multiple neurogenic tumors in the spinal canal are an under-recognized disease entity. Further studies for genetic aberration in multiple spinal neurogenic tumors are needed.