Intraosseous Schwannoma of the Mandible

Intraosseous benign peripheral nerve sheath tumor of the jaws: report of 4 new cases and a comprehensive literature review

Benign peripheral nerve sheath tumors (BPNSTs) are a vast, common, heterogeneous group of lesions that are often diagnostically challenging. The head and neck region is recognized as the second most common location for these lesions, especially the tongue. However, BPNSTs occurring centrally within the jaw bones are exceedingly rare. To date, approximately 161 cases of intraosseous BPNSTs have been reported in the jaws. This group mainly includes the relatively more common neurofibromas and schwannomas, and the less common perineuriomas and hybrid forms. Unlike soft tissues, schwannomas are the most common BPNSTs occurring within the jaws, followed by neurofibromas and perineuriomas. These neoplasms can present as a well-defined unilocular lesion or as an ill-defined multilocular image, resembling several types of benign and malignant lesions of odontogenic origin. The aim of the current study was to report 4 new cases of intraosseous BPNSTs and a comprehensive literature review.

Gnathic Schwannomas: A Report of Two Cases and Systematic Review of the Literature

BACKGROUND

The intraosseous schwannoma (IS) is a benign peripheral nerve sheath tumor postulated to arise de novo or from nerve fibers in preexisting nutrient canals. ISs are uncommon and comprise less than 1% of neoplasms originating in bone. We herein present two cases of mandibular schwannomas-the first case was a 66-year-old female with a four-month history of pain and pressure associated with an anterior mandibular radiolucency, and the second case was an asymptomatic 12-year-old female with separate radiolucencies of her mandibular symphysis and right posterior mandible. Incisional biopsies of all three lesions showed a benign spindle cell neoplasm with histologic features of a schwannoma; the tumor cells were strongly reactive for S-100. The patients underwent complete enucleation of their lesions and are without evidence of disease at ten months and five years, respectively.

METHODS

A systematic review was undertaken to evaluate the diagnostic features, treatment, and patient outcomes of gnathic schwannomas.

RESULTS

A total of 93 cases were identified with the following demographic findings: predominance in females (57%); average age of occurrence of 37.3 years (8 to 77 years); mean size of 3.6 cm; and involvement of the mandibular body (37.6%), mandibular body and ramus (18.3%), and anterior mandible (18.3%). The predominant clinical sign was swelling (69.9%), and the most common radiographic presentation was a radiolucency (94.6%) with well-defined borders (72%).

CONCLUSION

All cases were treated surgically, with an average follow-up interval of 22.9 months and a recurrence rate of 5.4.

Imaging Features of Intraosseous Schwannoma: A Case Series and Review of the Literature

To characterize the imaging features of patients with pathologically confirmed intraosseous schwannoma (IOS), institutional pathology and imaging databases were searched for IOS cases over a period of 17 years. A musculoskeletal radiologist evaluated all imaging studies. Additionally, a literature search was performed to identify IOS cases that had imaging findings of at least two modalities. Six patients (one female, five males, mean age of 50 ± 14 years) with IOS were identified, with all lesions localized to the lumbosacral region. Radiographic imaging was available in four patients, while all patients underwent CT and MR imaging. Radiographs depicted lytic lesions, and CT depicted heterogeneous expansile lesions with centrally hypodense areas and peripheral sclerosis. All cases involved extra-osseous extension, producing a mass effect on adjacent soft tissues and nerve roots. On MRI, the neoplasms displayed iso- to- slightly- low signal intensity on T1-weighted images and hyperintense signal intensity on T2-weighted images with heterogeneous enhancement. The literature review resulted in 102 IOS cases, which to the best of our knowledge, is the largest review on IOS, and the imaging findings of the previously published cases were the same as our cases. IOSs are rare benign neoplasms that should be considered in the differential diagnosis of well-defined expansile lytic lesions with sclerotic borders. This is particularly important in middle-aged adults with mandibular, sacral, or vertebral body mass.

Comprehensive Analyses of Intraoral Benign and Malignant Nerve Sheath Tumors: The Rare Disease Entities Revisited

INTRODUCTION

Intraoral benign and malignant nerve sheath tumors (BNST and MNST) are rare tumors with non-specific clinical presentations and represent diagnostic and therapeutic challenges. Current knowledge regarding their demographic, clinicopathological features and treatments remains fragmented.

MATERIALS AND METHODS

The original data about patients diagnosed as intraoral BNST and MNST were retrieved from our disease registry (2005-2017). Comprehensive reviews of English and Chinese literature were performed to collect and analyze the epidemiological, clinicopathological data and treatment outcomes about those published cases.

RESULTS

Thirty-four intraoral BNSTs were found at our institution in the past 13 years. Literature reviews identified 354 intraoral BNSTs in 223 articles and 60 intraoral MNSTs in 50 articles. Most intraoral BNSTs and MNSTs were presented in the second to fifth decade of life. Males outnumbered females in MNSTs, while BNSTs displayed a slight female preponderance. The common sites for intraoral BNSTs were parapharyngeal space followed by tongue, whereas mandible was the most common site for MNSTs. Most intraoral BNSTs were presented as slow-growing, painless mass or swelling, while MNSTs usually appeared as painful and invasive mass with discomfort. Surgical excision was preferred for intraoral BNSTs with excellent prognosis. Complete resection was indicated for intraoral MNST with dismal prognosis as evidenced by much recurrence, metastasis, and death.

CONCLUSION

Intraoral BNST and MNST are rare diseases which should not be ignored when intraoral painless or painful mass/swelling is found. Surgical excision is indicated for intraoral BNST with favorable outcomes. However, further investigations are warranted to optimize the treatment for intraoral MNST to improve its prognosis.

Intraosseous schwannomas of the jaws: 2 case reports and review of the literature

Schwannomas are one of the benign neoplasms originating from the neural sheath. Soft tissues of the head and neck are the most common sites of occurrence; however, intraosseous schwannomas are rare. This article documents 2 cases of intraosseous schwannoma that presented as a submandibular mass and provides a review of the literature on intraosseous schwannomas.

Central neurilemmoma of the jaw in concurrence with radicular cyst: a case report

We report the features of a central neurilemmoma in the mandible of a patient having an inflammatory apical dental (radicular) cyst in the same region. A 29-year-old woman complained of numbness on the right side of the lower lip of 3 months duration and noted following endodontic therapy to the right mandibular first molar tooth. Panoramic radiography revealed a bilocular radiolucency in the right body of the mandible. Excisional biopsy was performed. The histopathology revealed neurilemmoma of the mandible in concurrence with inflammatory apical dental (radicular) cyst. No recurrence was detected during a 1-year follow-up.