Intraneural perineurioma in neurofibromatosis type 2 with molecular analysis.

Intraneural perineuriomas are rare benign neoplasms. The gene associated with neurofibromatosis 2 (NF2) is located on chromosome 22q12, and mutations in NF2 are commonly seen in soft tissue perineuriomas. However, an association between NF2 mutations and intraneural perineuriomas (INPs) has not been well established. We present a 20-year-old male with NF2, multiple schwannomas and an intraneural perineurioma in the radial nerve at the spiral groove. Sequencing of NF2, SMARCB1, and LZTR1 was performed and demonstrated loss of the long arm of chromosome 22 including NF2, SMARCB1, and LZTR1, and a constitutional NF2:c.(-4577_-854)_(45-185)del alteration. We review the literature supporting two mutually exclusive pathways involving NF2 and TRAF7 mutations that lead to the development of INPs.