Other Nerve Sheath Tumors of Brain and Spinal Cord

The three main types of nerve sheath tumors are schwannomas, neurofibromasNeurofibroma and perineuriomasPerineurioma. Multiple neurofibromas throughout the body are the hallmark of Neurofibromatosis type 1Neurofibromatosis type 1 (NF1) (NF1). Spinal nerve sheath tumorsSpinal nerve-sheath tumors are classified in the group of intradural extramedullaryIntradural extramedullary spinal cord tumorsSpinal cord tumor, in which they are the most common type (25–30%). Their incidenceIncidence is 3–4 per 1 million people. Spinal schwannomas are encountered sporadically or in the context of Neurofibromatosis typeNeurofibromatosis type 2 (NF2) 2, while neurofibromasNeurofibroma are typical for patients with Neurofibromatosis type 1. Neurofibromas are composed predominantly of Schwann cellsSchwann cells and fibroblastsFibroblast, alongside which are also found axons, perineurial cells, mast cells and extracellular matrixMatrix. Most of the neurofibromas are asymptomaticAsymptomatic. Any increase in the size of a neurofibroma or the presence of painPain is an indicator of a possible malignantMalignant degeneration. NeurofibromasNeurofibroma are treated surgically. Neurofibromas involve the whole nerve and cause its fusiform enlargement which makes it impossible to preserve the nerve's functions if complete tumor removal is performed. Hence, such tumors are initially observed. In case of progressive growth, the options are either resection of the tumor and immediate reconstruction with a peripheral nerve graft (e.g., nerve suralis interposition graft) or subtotal removal and follow-upFollow-up. Malignant peripheral nerve sheath tumorsMalignant peripheral nerve sheath tumors (MPNST) (MPNST) are very rare tumors with incidenceIncidence of around 1 per 1,000,000 people. MPNST account for 3–10% of all soft-tissue sarcomasSarcomas. The most common initial symptom of MPNST is a painless mass. Any rapid increase in a subcutaneous mass or rapid onset of symptoms should raise the suspicion of a malignant tumor. In patients with diagnosed NF1Neurofibromatosis type 1 (NF1), the recent rapid increase in a known lesion should raise the suspicion of malignantMalignant degeneration of the lesion and opt for active treatment. In the case of MPNST a wide surgical excisionExcision is advocated. The resectability depends greatly on the location of the tumors and varies from around 20% in paraspinal MPNST and reaches 95% in MPNST localized in the extremities. MPNSTMalignant peripheral nerve sheath tumors (MPNST) are a rare disease and should be managed by a multidisciplinary team of neurosurgeons, radiologists and oncologists.