Benign peripheral nerve sheath tumor

Benign peripheral nerve sheath tumors (BPNSTs) are a group of non-cancerous neoplasms that arise from the cells surrounding peripheral nerves, including Schwann cells, perineurial cells, and fibroblasts. This category encompasses several distinct tumor types, most notably schwannomas (neurilemmomas), neurofibromas (including localized, diffuse, and plexiform variants), and perineuriomas. These tumors can develop along any peripheral nerve in the body, affecting the skin, soft tissues, and deeper structures including the spinal nerve roots and major nerve plexuses. They may occur as isolated sporadic lesions or in the context of genetic predisposition syndromes such as neurofibromatosis type 1 (NF1), neurofibromatosis type 2 (NF2), or schwannomatosis. Key symptoms depend on the tumor's location and size. Many BPNSTs are asymptomatic and discovered incidentally, but they can cause localized pain, tingling, numbness, or weakness in the distribution of the affected nerve. A palpable mass may be noted along the course of a peripheral nerve, sometimes with a positive Tinel sign (tingling upon tapping). Plexiform neurofibromas, which are pathognomonic for NF1, can cause significant disfigurement, functional impairment, and carry a risk of malignant transformation to malignant peripheral nerve sheath tumors (MPNSTs). The primary treatment for symptomatic BPNSTs is surgical excision, with the goal of preserving neurological function. Schwannomas are typically well-encapsulated and can often be removed with minimal nerve damage, while neurofibromas are more intimately associated with the nerve and may be more challenging to resect without causing neurological deficit. For patients with NF1-associated plexiform neurofibromas, the MEK inhibitor selumetinib (Koselugo) has been approved for pediatric patients with symptomatic, inoperable tumors. Observation with serial imaging is appropriate for asymptomatic or stable tumors. Long-term monitoring is recommended, particularly for plexiform neurofibromas, due to the potential risk of malignant transformation.

Common questions about Benign peripheral nerve sheath tumor