Mandible schwannoma (neurilemmoma) presenting as periapical lesion.

Schwannoma is a benign nerve tumour that originates from Schwann cells, which cover peripheral nerves. Intraosseous schwannoma of the jaw is rare. Primary schwannoma of the mandible presenting as a periapical radiolucency on a non-vital endodontically treated tooth has rarely been referred to in the English medical literature. A rare case of intraosseous schwannoma is reported in a 23-year-old woman. The patient presented clinically with a painful swelling on the right side of the mandible and with a radiologically ill-defined unilocular periapical lesion around the mesial root of the endodontically treated first molar. Surgical treatment involved complete excision of the lesion with a mesial and distal root resection. Histological and immunohistochemical examination showed that the lesion was a primary intraosseous schwannoma of the mandible. Immunohistochemical examination showed a positive and strong reaction for S-100 protein, characteristic of neural tumours. 1 year following surgery, there were no regional recurrences. Radiographically, mandibular intraosseous schwannoma is difficult to differentiate from bone tumours such as ameloblastoma, myxoma, fibrous dysplasia, neurofibroma, central giant cell lesion or periapical lesion, so it should be included in the list of possible periapical pathoses.