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

Abnormal widening of the mandibular canal -A characteristic and valuable imaging phenomenon

Abnormal widening of the mandibular canal (MC) is rarely observed on radiography. Nonetheless, as most of the current research on abnormal mandibular widening is limited to case reports and MCs have relatively deep and hidden positions, there are challenges in diagnosing and formulating treatment plans for patients with abnormal MC widening. To provide ideas for the differential diagnosis and treatment choices of the characteristic clinical sign, this study included patients with abnormal widening of the MC between July 2014 and October 2023. The patient's medical records were reviewed, general information, disease details and radiographic features (panoramic reconstructive computed tomography) of MC widening were collected. Patients were followed up to assess treatment outcomes. In conclusion, the abnormal widening of the MC often implies a pathological state of the mandible. And different morphologies of the widened MC are helpful for differential diagnosis of protential mandibular disease.

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.

Intraosseous schwannoma of the mandible: new case series, literature update, and proposal of a classification

Intraosseous schwannoma of the mandible is rare, with diagnostic and therapeutic challenges. The aims of this study were to report new cases of intraosseous schwannoma of the mandible and to propose a clinical classification, providing suggestions for treatment methods. The cases of 13 patients treated at the authors' hospital and 86 cases reported previously in the literature were reviewed. The most common clinical feature was facial swelling (60/93). The rate of cortical thinning or expansion was 44.8% (43/96); widening of the inferior alveolar nerve canal on radiographs was observed in 15 patients.

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.

Intraosseous schwanomma: A rare case report

Intraosseous schwanommas are benign tumors that arise from Schwann cells. They are common in soft tissues of the head and neck region. However, intraosseous schwanommas are rare accounting for less than 1% of all bone tumors. They commonly manifest as a swelling that is usually asymptomatic. They can be treated with simple enucleation and curettage with a low rate of recurrence and malignant transformation. Histopathology alone is insufficient for arriving at a definitive diagnosis. Immunohistochemistry plays an important role in such cases for correctly establishing and confirming the diagnosis. Here, we present a rare case of intraosseous schwanomma (neurilemmoma) of the mandible.

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.

Intraosseous ancient Schwannoma: A rare case in the mandible and a literature review

Schwannoma, otherwise known as neurilemmoma, is a benign tumor that originates from Schwann cells. Ancient Schwannoma is a long-standing Schwannoma with degenerative and xanthomatous changes. The Head and neck region is one of the most common sites for nerve sheath tumors but Involvement of the jaw is a considerably infrequent event. We report a rare case of intraosseous ancient Schwannoma of the mandible in a 24-year-old male patient which was initially misdiagnosed with carcinoma. The clinical features, radiographic findings, and treatment plan are discussed. Furthermore, a thorough literature review demonstrated nine published cases of intra-osseous ancient Schwannoma with their summarized features. Recognition of various histopathologic features of ancient Schwannoma is essential to prevent over-treatment.

Intraosseous schwannoma of the glenoid: case report and literature review

Intraosseous schwannomas represent an extremely rare subgroup of schwannomas, accounting for <1% of all primary bone tumors. They mostly occur in the mandible, the maxilla, the sacrum, and they are also seen in long bones. We herein report a rare presentation of an intraosseous schwannoma in the glenoid of a 49-year-old patient. She complained of shoulder pain and was referred to the orthopaedic oncologist after detection of a suspicious lesion on imaging. Biopsy revealed benign spindle cells and immunohistochemistry was positive for S100. Because of the rarity of these intraosseous schwannomas it is important to recognize their radiological and histological features and make a differential diagnosis with other lytic tumors. Only if these characteristics are recognized, correct treatment can be given with definite curettage and bone grafting and correct follow-up with avoidance of unnecessary adjuvant therapy.

Oral neural tumors: Clinicopathologic analysis of 157 cases and review of the literature

Background

Oral neural tumors (ONTs) are rare lesions and represent reactive or neoplastic proliferations of nerve sheath cells. The purpose of the present study is to report the clinical, demographic and histopathologic features of 157 ONTs diagnosed in a single Oral Pathology Department and review the pertinent literature.

Material and Methods

157 cases of ONTs diagnosed during a 44-year period were retrospectively collected and the diagnosis was reconfirmed by studying representative haematoxylin and eosin stained tissue sections. The patients’ gender and age, as well as the main clinical features of the lesions, were retrieved from the biopsy submission forms.

Results

The 157 ONTs represented approximately 0.4% of 35,590 biopsies accessioned during the study period. They affected 71 male and 86 female patients with a mean age of 38.4±18.8 years. They mainly appeared as asymptomatic nodules of normal or white colour on the tongue, lip mucosa and hard palate. The most common ONT was granular cell tumour (38.9%) followed by neurofibroma (19.7%), schwannoma (15.9%), traumatic neuroma (15.9%), palisaded encapsulated neuroma (8.3%) and nerve sheath myxoma (1.3%).

Conclusions

This study confirmed the rarity of ONTs. Their clinical characteristics mimic other oral lesions; thus, microscopic examination is the only mean to arrive at a definitive diagnosis.

Key words:Oral neural tumors; oral neural neoplasms; neurofibroma; oral neurofibroma; schwannoma; oral schwannoma; neurilemmoma; oral neurilemmoma; granular cell tumor; oral granular cell tumor; traumatic neuroma; oral traumatic neuroma; palisaded encapsulated neuroma; oral palisaded encapsulated neuroma.

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.

Diagnostic challenges of an unusually large schwannoma of the mandible: Report of a case

Schwannomas are slow-growing, benign neoplasms arising from the Schwann cells and are commonly reported as peripheral tumors in the head and neck region. Central intramandibular schwannomas are extremely rare lesions. We report a case of intramandibular schwannoma in a 70 year old male patient. Panoramic radiography revealed a large, multilocular radiolucent lesion with distinct borders involving the right mandibular body and ramus. A complete excision was achieved by removing the tumor followed by reconstruction of the mandible. The clinical, radiological, and histopathological features are discussed within the context of this case.

Parapharyngeal Schwannoma of the Mandibular Nerve Associated With Auditory Changes

We present a case of a parapharyngeal schwannoma of the mandibular nerve with intraosseous extension into the mandible. The initial symptoms included decreased auditory acuity, with subsequent magnetic resonance imaging findings suggestive of Eustachian tube obstruction. This represents a rare symptom of schwannomas of the mandibular nerve. Owing to the degree of bony expansion and cortical thinning of the adjacent mandibular ramus, concern existed for a pathologic fracture. Treatment involved complete excision of the lesion using hemimandibulectomy with second stage reconstruction. The patient noted resolution of the preoperative symptoms. No sign of recurrence of the schwannoma was noted at the 2-year mark.

Association between intraosseous schwannoma occurrence and the position of the intraosseous nutrient vessel: A case report

Intraosseous schwannoma is a rare benign bone tumor that originates from Schwann cells of the nerve sheath. The majority of intraosseous schwannomas arise in the mandible and sacrum, but an intraosseous schwannoma involving the ulna is described in the present case report. Radiologically, the current case presented as a well-defined lytic lesion, with a pathological fracture and no intralesional calcification, in the proximal metaphysis of the left ulna. Using magnetic resonance imaging, an intraosseous mass spreading out from the cortical defect was observed. The lesion appeared isointense to skeletal muscle on T1-weighted images, and hyperintense or heterogeneous on T2-weighted images. The differential diagnosis comprised benign bone tumors, including bone cyst, aneurysmal bone cyst, giant cell tumor and fibrous dysplasia. Based on the results of a needle biopsy, a schwannoma involving the ulnar bone was diagnosed, and tumor marginal resection followed by artificial bone grafting and fixation was performed. A total of one year subsequent to surgery, the patient exhibits no symptoms, and there is no evidence of disease recurrence.

Intraosseous schwannoma of the ilium

We presented a 27-year-old male diagnosed with intraosseous schwannoma of the ilium. Computed tomographic images revealed a well-demarcated, lobulated, expansile, osteolytic lesion in the right supraacetabular region of the ilium. In addition, an intratumoral punctate calcification and a sclerotic rim were observed. T2-weighted magnetic resonance (MR) images demonstrated a heterogeneously hyperintense lesion with a hypointense rim. Major parts of the lesion, excluding some central areas, were enhanced on gadolinium-enhanced MR images. Pathological examination revealed an intraosseous schwannoma. Our findings indicate that intraosseous schwannoma should be considered when images demonstrate a well-demarcated, lobulated, expansile, osteolytic lesion with a sclerotic rim.

Large foot schwannoma with bone invasion - a case report

A rare case of a large foot schwannoma with an intraosseous component is presented. Due to suspicion of malignancy, an amputation had previously been proposed. When the patient presented to us, the prolonged clinical course as well as some elements of the imaging exams suggested benignancy and we decided for complete tumor excision. Intraoperative findings supported the benign character of the neoplasm and pathology would later confirm the diagnosis of a benign schwannoma. The outcome, at 18 months of follow-up was a fully functional limb. Recurrence must still be considered but malignant transformation is very rare in a solitary schwannoma and can be discounted. Solitary benign schwannomas have a negligible malignization potential independently of their size or osseous component. When benignancy is considered, primary total tumor excision, as part of a staged procedure, is a safe approach. It allows for a thorough pathologic examination and eventually for a definitive treatment.

Intraosseous schwannoma originating in inferior alveolar nerve: a case report

Schwannomas (neurilemmomas) are benign neoplasms derived from Schwann cells of the neurilemma and appear most frequently on the auditory nerve or peripheral nerves of the skin. They arise in the oral and maxillofacial region infrequently, and very rarely in the center of the jaw. We herein present a case of a rare mandibular intraosseous schwannoma derived from the main trunk of the inferior alveolar nerve in a 33-year-old man. Fusiform expansion in the mandibular canal was observed and a mass showing the target sign in the mandibular canal was confirmed on T2-weighted and Gd contrastenhanced T1-weighted MRI. Based on these findings, an inferior alveolar nerve-derived schwannoma or other benign nervous system neoplasm was diagnosed. A buccal side cortical bone flap in the mandibular molar region was removed to expose the mass, which was then peeled away from the nerve fibers and completely removed. Some inferior alveolar nerve fibers that were connected to the mass were removed at the same time, but the remaining nerve fiber bundle was preserved. Histopathology confirmed the diagnosis of a schwannoma with Antoni type A and Antoni type B regions. Although the patient experienced extremely mild paresthesia in the skin over the mental region and mental foramen at immediately after surgery, this had almost entirely disappeared at 7 years and 4 months later, and there has been no tumor recurrence.