Mental Nerve Schwannoma - A Rare Cause of Lower Jaw Swelling

Abstract

Schwannomas are relatively rare benign neoplasms of neurogenic origin from the neural sheath of peripheral nerves occurring more commonly in the head and neck. Mandibular bone is the commonest site of occurrence of these nerve lesions. Radiographically, intraosseous schwannoma of mandible is very difficult to differentiate from other bony pathologies such as neurofibroma, ameloblastoma, fibrous dysplasia, myxoma, central giant cell lesion, or periapical lesion, so it should be included in the differential diagnosis of lower jaw swelling. Schwannoma as a pathologic entity was first reported in 1910 by Verocay. Schwannoma (also known as neurinoma, neurolemmoma, neurilemmoma, perineural fibroblastoma, and peripheral nerve sheath tumour) is a rare, slowgrowing, benign neurogenic neoplasm that originated from Schwann cells. Schwann cells cover myelinated sheath of nerve fibres.1 These intraosseous schwannomas account for not more than 1 % of the central neoplasms. More than one third of all schwannomas are found in the head and neck region. 2 Most of these originate from the lower cranial nerve and sympathetic nervous system. Schwannomas from the upper cranial nerves such as trigeminal nerve and its branches are less common. Other commonly reported sites include the vertebra, clavicle, ribs, sacrum, humerus, ulna radius, etc. This painless slow-growing neoplasm may develop at any age.