Nerve sheath tumours

Excerpt

Neurofibromas and schwannomas are benign tumours of the peripheral nerve sheath. They are encountered within a wide range of medical specialities and may occur as isolated sporadic lesions or as a key feature of genetic disorders including schwannomatosis, neurofibromatosis type 1 (NF1) and neurofibromatosis type 2 (NF2). Approximately half of cases of NF1 and NF2 are the result of autosomal dominant inheritance of a germline mutation from an affected parent, whilst the remainder are caused by de novo mutations. NF1 is caused by mutations in the NF1 gene on chromosome 17q11.2, and NF2 is caused by mutation of the NF2 gene at locus 22q12.2. Despite considerable phenotypic overlap with NF2, schwannomatosis has been shown to a distinct entity with pathological variants in SMARCB1 and LZTR1 genes. NF1 is the most common of the three conditions, with a frequency of 1 in 2500–3000 live births, whereas NF2 and schwannomatosis are considerably less common. …