Intra-Osseous Degenerated Neurilemmoma of the Mandible in a 23 Year-Old Woman

Neurilemoma is a benign tumor derived from peripheral nerve sheath and is uncommon in the oral cavity and especially in the jaw bones. The treatment of neurilemmoma is total surgical resection and the chance of recurrence is very low. Chronic lesions may undergo microscopic degenerative changes. In this case, the lesion is called degenerated neurilemmoma or ancient schwannoma which is a rare entity. Here, we report a degenerated neurilemmoma in the lower jaw bone and compare its histopathologic characteristics with neurilemmoma of the oral cavity and jaw bones reported elsewhere. The patient was a 23 year-old woman who chiefly complained about pain and swelling in her lower jaw. According to her, she had undergone a surgery 6 years ago on the same site of her jaw but had no idea of the diagnosis of the lesion. Based on microscopic evaluation and S-100 immunohistochemistry of a new biopsy in which benign proliferation of schwan cells with nuclear atypia, hyalinization, calcification and myxomatous changes were detected, the diagnosis of a degenerated neurilemmoma was verified. Partial resection with healthy margins in addition to transmandibular curettage of the intraosseous lesion was performed. The resected bony segment was freezed and replaced. Discussion & Neurilemmoma is a benign tumor of peripheral nerve sheath origin. If it is left untreated for a long period of time, clinical, radiographic and histopathologic changes are likely. Considering special histopathologic views helps differentiate it from other similar lesions. The proper diagnosis will affect the course of treatment.