PLEXIFORM SCHWANNOMA INVOLVING THE ANTERIOR MANDIBLE

Abstract

<h3>BACKGROUND</h3> Schwannomas and neurofibromas are common benign neoplasms originating from the peripheral nerves. These neoplasms originating in the oral and para-oral tissues, especially involving the jaw, are extremely rare. Plexiform schwannoma is a unique variant in which the Schwann cells demonstrate a unique plexiform pattern. A literature search revealed only 2 case reports of plexiform schwannoma involving the jaws. <h3>CASE REPORT</h3> A 47-year-old male patient was referred for consultation by his dentist for evaluation and diagnosis of a radiolucency in the anterior mandible with no apparent odontogenic/clinical etiology. The patient complained of sensitivity in this region and occasional radiating pain. Clinical examination showed no signs of infection or inflammation. The patient denied any known medical disease or history of surgeries. Cone beam computed tomography examination revealed a large, well-defined, hypodense, partially corticated lesion in the anterior mandible with evidence of impingement of the facial cortex, resulting in a scooped-out defect. The radiologic differential interpretation included peripheral ameloblastoma and peripheral giant cell granuloma. An incisional biopsy was recommended to determine the nature of this entity. Microscopic examination revealed a multicircumscribed, lobular mass bounded by a thin fibrous connective tissue capsule. Each lobule was composed of streaming fascicles of spindle-shaped cells, some of which formed a palisading arrangement. Immunohistochemistry was positive for protein S-100 and epithelial membrane antigen, which confirmed the diagnosis of plexiform schwannoma. <h3>DISCUSSION/CONCLUSIONS</h3> This is an unusual case of a unique variant of schwannoma, in this case a plexiform type, which is an extremely rare neurogenic neoplasm. This atypical presentation and location of the lesion, which mimics other peripheral benign neoplasms, highlights the importance of a systematic workup with the aid of the appropriate diagnostic tools for ideal patient care. It demonstrates the important role of immunohistochemistry to confirm the nature of this entity.