Intraneural perineurioma

An intraneural perineurioma is a rare benign tumor within the sheath of a single nerve that grows but typically does not recur or metastasize. These lesions are only composed of perineurial cells, cloned from a single cell. They are distinct from schwannoma and neurofibroma.

Intraneural perineurioma is a neoplastic proliferation of perineurial cells with unique immunohistochemistry and ultrastructural features, and it is distinct from other onion bulb Schwann cell-derived entities. Despite harboring molecular abnormalities of the long arm of chromosome 22, intraneural perineurioma has not been associated with neurofibromatosis.^[1]

Due to the involvement of one or more nerve fascicles, intraneural perineuriomas are distinguished by a localized, solitary expansion of peripheral nerves. These tumors develop slowly or stay stable over time.^[2]