Perineuriomas present as focal intraneural peripheral nerve or isolated soft tissue lesions. In this case report, we focus on the intraneural variant of perineurioma. Intraneurial perineurioma which generally presents as a slowly progressive painless focal motor neuropathy characterized slowly histologically by onion-bulb shaped whorls, was first described by Imaginario et al.[] in 1964. The etiology of these lesions has been controversial with some authors asserting that this lesion is a reactive process associated with trauma and other proposing that the lesion is a true neoplasm[-]. Thus the lesion has been labeled with different names including ‘localized hypertrophic mononeuropathy' and ‘perineuroma'[,-]. The evidence relating these lesions to trauma has been scarce, and both intraneurial and extraneurial variants are now believed to represent clonal neoplasms associated with abnormalities of chromosome 22[,]. However, in recent literature the lesion continues to be referred to interchangeably as perineurioma and localized hypertrophic mononeuropathy[,].

We present a case of a median nerve perineurioma which has caused carpal tunnel syndrome and treated by surgical procedures. [Turk J Cancer 2009;39(4):158-160]