Unbalanced t(2;19) and t(2;16) in a neurofibroma

Abstract

Neurofibromas are a benign heterogeneous group of tumors arising from peripheral nerve sheaths; they consist of a mixture of Schwann cells, fibroblasts, perineural cells, neuronal processes, and mast cells. Neurofibromas may present as dermal (cutaneous or subcutaneous) or plexiform (diffuse growths, spinal tumors, nodular or diffuse) tumors. They may present as isolated sporadic tumors in the general population or occur as a part of an autosomal dominant tumor diathesis in von Recklinghausen neurofibromatosis type 1 (NF1). Malignant transformation of neurofibromas gives rise to nerve sheath tumors (MPNSTs) and neurofibrosarcoma in NF1 patients [1]. Although the genetic basis of neurofibromas associated with NF1 has been well established, similar genetic basis of sporadic neurofibromas is poorly understood [2]. Loss of both alleles of NF1 occurs in MPNSTs and associated tumors [3], but such evidence in benign neurofibromas is lacking. Loss of heterozygosity (LOH) at the NF1 locus has been detected in a minority of dermal neurofibromas of NF1 syndrome [2]; however, no such evidence exists in sporadic neurofibromas. Thus, these findings suggest that sporadic neurofibromas may arise through a mechanism different from that of NF1 tumors and the understanding of the genetic mechanisms that underlie tumorigenesis remains elusive.