Perineurioma and Malignant Peripheral Nerve Sheath Tumor
Arising from perineurial cells within the peripheral nerve sheath, perineurioma is a benign neoplasm with advanced perineurial differentiation, presenting as intraneural perineurioma, soft tissue perineurioma, and sclerosing perineurioma. It often occurs in the background of neurofibromatosis type 2. The nervous system of humans comprises two parts: the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and spinal cord, the PNS encompasses the cranial nerves, spinal nerves, peripheral nerves, and neuromuscular junctions. Intraneural perineurioma is a rare tumor. It commonly affects adolescence to early adulthood and shows no gender predilection. Depending on the nerve involved, intraneural perineurioma may manifest as progressive muscle weakness, localized muscle atrophy, nonpalpable mass, pain in affected regions, and sensory disturbance. Intraneural perineurioma often causes segmental, uniform expansion of the nerve. Intraneural perineuriomas that are small and easily resectable generally have an excellent prognosis.