Intraoral Schwannomas: Presentation of a series of 12 cases

Case of submandibular schwannoma and review of literature

Schwannomas are slow growing, benign tumours arising from Schwann cells. They are usually solitary and are sometimes associated with Neurofibromatosis type 1 and 2. As reported by Okada et al., while approximately 25%-40% of extra-cranial schwannomas occur in the head and neck region, Schwannomas of the oral cavity are very uncommon, accounting for only 1% of all Schwannomas. We report a case of a sublingual schwannoma in a 47-year-old female, discovered incidentally during the workup for tinnitus. The radiological and histopathological findings, along with a literature review, are presented.

A rare case of upper lip schwannoma: A case report with analysis of the histological, immunohistochemical and pathogenesis aspects

INTRODUCTION AND IMPORTANCE

Schwannoma, a benign tumor originating from Schwann cells, is a rare case found intraorally. The tongue, palate and buccal mucosa are the most common sites of intraoral Schwannoma while it is very rarely found on the lips. Previous studies reported only twelve cases of Schwannoma on the upper lip. The etiology of Schwannoma is unknown, but in some literature, Schwannoma occurs due to a defect in the NF2 gene. Management of Schwannoma is excision of the capsule. The prognosis is good, and the recurrency is low. This article reports a rare case of upper lip Schwannoma in adolescent and its management with its histological, immunohistochemical and pathogenesis aspects.

CASE PRESENTATION

A 16-years old female presented a painless, semi-solid, mobile lump on the upper lip measuring of approximately 1.5 × 3 cm that had similar color with the surrounding tissue. The lump appeared 7 years ago.

CLINICAL DISCUSSION

Excision of the capsule and margins of the tumor. Histopathological examination showed a unique feature of Schwannoma, the Verocay bodies. Subsequent immunohistochemical examination of S100 protein showed a classic type of Schwannoma.

CONCLUSION

Upper lip schwannoma is a very rare tumor, and this type of tumor cannot be distinguished from other benign soft tissue tumors based on clinical findings. Immunohistochemical results are in accordance with the Histopathological results for the final diagnosis of Schwannoma. Schwannoma can be used as a differential diagnosis in cases of lumps on the lips with sessile, similar color like surrounding tissue, painless, and movable features.

Oral palisaded encapsulated neuroma; a diagnosis seldom suspected clinically

Key Clinical Message

Palisaded encapsulated neuroma (PEN) is generally seen in the head and neck area as an asymptomatic nodule with the same color as the surrounding skin and rarely occurs in the oral cavity. The exact etiology of PEN is not known, but there is evidence supporting the role of trauma as its etiological factor.

Abstract

Palisaded encapsulated neuroma (PEN) is one of the benign nerve sheath tumors of Schwann cell origin, which is commonly found in the skin of the head and neck area, and rarely occurs in the oral cavity. Its exact etiology is unknown, but there is evidence that supports the role of trauma as an etiological factor. Here we present a case of PEN in the hard palate of a 30-year-old patient and review the differential diagnoses of these nerve sheath tumors of the oral cavity.

A Rare Case of Pediatric Oropharyngeal Schwannoma

This is a case of a male child who presented with a progressively enlarging oropharyngeal mass, hyponasal voice, and symptoms of obstructive sleep apnea. Computed tomography imaging of the head and neck revealed a well-circumscribed low-density area of polypoid morphology arising from the left lateral pharyngeal wall, filling most of the posterior oropharynx and extending to a pedicle at the lateral nasopharynx. Histopathological evaluation following surgical excision revealed Antoni A tissue and S100 immunoreactivity. The presentation and diagnosis of benign schwannoma neoplasms are discussed.

A rare case of left parapharyngeal space large schwannoma of unknown origin

Schwannoma, also called neurilemmoma, is a rare neurogenic tumor exclusively benign that develops from a variety of glial nerve cells called Schwann cells. We present a 26-year-old female patient who was admitted with a history of dysphagia, headache and swelling going from the lower limit of the ear to the floor of the neck on the left side, which has been slowly progressing for 5 years. Upon local clinical examination, a well-defined mass was revealed, 6 × 5 cm in size, non-painful spontaneously, painful on direct palpation of the left neck. Computed tomography scan has shown a well-circumscribed large mass with heterogenous areas of enhancement in the left parapharyngeal space displacing the submandibular gland superiorly and the carotid sheath anterolaterally and compressing the oropharyngeal airway. Excision of the tumor was done by a combined route without post-operative complications noted. Histopathological examination revealed a benign schwannoma without the identification of the nerve of origin.

Floor of mouth schwannoma mimicking a salivary gland neoplasm: a report of the case and review of the literature

Schwannomas or neurilemmomas are slow-growing, benign and often firm lumps that are typically painless. They are extremely rare in the oral cavity, with the tongue and the palate being the most common intraoral sites. This is a case report of this pathology in the floor of the mouth. We present a case of a 28-year-old female patient with a 2-month history of a floor of mouth swelling. On clinical examination this was non-tender and appeared firm. An ultrasound of the lesion was performed which revealed a well-defined, rounded and low reflective soft tissue mass. Following an MRI scan and surgical excision of the lesion, a definitive diagnosis of a schwannoma was made. The presence of schwannoma in the oral cavity is unusual. Based on the literature and the presented case, it should be considered as a differential diagnosis until the final histopathological confirmation.

Tongue Base Schwannoma

Intraoral schwannomas account for 1% of head and neck schwannoma, with tongue base schwannoma being reported rarely. In an English literature search from 1988 to 2014, not more than 38 cases of tongue base schwannoma have been reported. Large tongue base schwannomas pose a significant risk to airway, thereby calling for an early intervention. We report a rare case of tongue base schwannoma in a 25 year old female managed surgically by lateral pharyngotomy approach.

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.

Palatal schwannoma in a young female patient: report of a case and review of the literature

BACKGROUND

A few cases of oral schwannomas in paediatric patients have appeared in the literature so far; however, there are no studies focusing solely on paediatric oral schwannomas. The aim of this study is to report a case of palatal schwannoma in a young female patient and review the pertinent literature on oral schwannomas in paediatric patients.

CASE REPORT

A 12-year-old girl presented with a growing swelling of 2 weeks duration on the hard palate. With a provisional diagnosis of a salivary gland neoplasm an incisional biopsy was performed under local anesthesia and the histologic examination disclosed an Antony A type schwannoma.

TREATMENT

Complete surgical resection of the lesion was performed under local anaesthesia through a palatal mucosa incision and paraffin gauze was sutured on the surgical area for protection during secondary healing. The bone underlying the tumor was normal. The postoperative period was uneventful and 2 weeks after excision the gauze were removed.

FOLLOW-UP

There have been no signs of recurrence during a 18-month follow up period.

CONCLUSION

A palatal swelling in a child or adolescent may represent a neoplasm, such as a schwannoma and requires careful clinical and radiographic evaluation of the dentition.

Oral peripheral nerve sheath tumors: A clinicopathological and immunohistochemical study of 32 cases in a Brazilian population

Background

Oral peripheral nerve sheath tumors (OPNSTs) are reactive or neoplastic diseases that develop from proliferation of the nerve itself or their limiting sheaths. Here we describe the clinicopathologic data of OPNSTs observed in a sample of the Brazilian population and evaluate the expression of molecules associated with neural biology to determine their usefulness in the diagnosis.

Material and Methods

Descriptive study of cases diagnosed as OPNSTs, from the Pathology Laboratory at the School of Dentistry/ Federal University of Uberlandia, followed by an immunohistochemical study of S-100, CD57, neurofilament protein (NFP) and epithelial membrane antigen (EMA).

Results

OPNSTs comprised 0.27% of all biopsies. There were eight patients with neurofibromas, eight with traumatic neuromas, seven with schwannomas, five with granular cell tumor (GCT), and four with palisaded encapsulated neuromas (PEN). Women were more frequently affected (60.6% of the cases). Tongue and lips prevailed as the most frequent sites. S-100 was reactive in 100% of the cases. Neural fibers evidenced by CD57 reactivity of their Schwann cells were always nested in bundles within neurofibromas and GCT, absent within schwannomas and dispersed within PEN. Reactivity for NFP was limited to axons and then followed the same pattern of CD57, though much less evident. Reactivity for EMA was observed in the capsular tissues and perineurium of nerve fascicles, and absent in parenchymal cells of GCT.

Conclusions

This study showed that OPNSTs are rare, widely benign and often found in tongue and lips. OPNSTs evolve from a common origin to distinct histological patterns, with eventual overlapping in their clinical and morphologic features. The arrangement of reactive residual neural fibers for CD57 can be a useful staining in the differential diagnosis of OPNSTs. Key words:Peripheral nerve sheath tumors. Oral cavity. Differential diagnosis. Immunohistochemistry. CD57 antigens.

Peripheral Exophytic Oral Lesions: A Clinical Decision Tree

Diagnosis of peripheral oral exophytic lesions might be quite challenging. This review article aimed to introduce a decision tree for oral exophytic lesions according to their clinical features. General search engines and specialized databases including PubMed, PubMed Central, Medline Plus, EBSCO, Science Direct, Scopus, Embase, and authenticated textbooks were used to find relevant topics by means of keywords such as “oral soft tissue lesion,” “oral tumor like lesion,” “oral mucosal enlargement,” and “oral exophytic lesion.” Related English-language articles published since 1988 to 2016 in both medical and dental journals were appraised. Upon compilation of data, peripheral oral exophytic lesions were categorized into two major groups according to their surface texture: smooth (mesenchymal or nonsquamous epithelium-originated) and rough (squamous epithelium-originated). Lesions with smooth surface were also categorized into three subgroups according to their general frequency: reactive hyperplastic lesions/inflammatory hyperplasia, salivary gland lesions (nonneoplastic and neoplastic), and mesenchymal lesions (benign and malignant neoplasms). In addition, lesions with rough surface were summarized in six more common lesions. In total, 29 entities were organized in the form of a decision tree in order to help clinicians establish a logical diagnosis by a stepwise progression method.

Intraoral ancient schwannoma: A systematic review of the case reports

Intraoral ancient schwannoma is a rare type of oral schwannoma, which is encapsulated and well demarcated from the surrounding tissues. Ancient schwannomas are associated with conventional features of neurilemmoma; however, they are distinguished from other types of schwannoma due to factors such as the long history, cellular architecture showing hypocellularity, and hyalinized matrices. This systematic review was performed through searching in databases such as PubMed and Google Scholar using related keywords (intraoral, oral, ancient, schwannoma, and neurilemmoma). Eventually, 26 case reports were systematically reviewed by the researchers. Required data were extracted by one researcher, and all the selected articles were reviewed in full text after screening. This systematic review aimed to determine the most significant influential factors in intraoral ancient schwannoma and evaluate the diagnostic and therapeutic methods in this regard.

Conflation of gingival overgrowth and schwannoma

The authors describe a seminal case report of a 10-year-old boy with enlarged gingivae in relation to his maxillary anterior teeth. The lesion, provisionally diagnosed as idiopathic gingival enlargement, was completely excised and divided into two sections. The histological and immunohistochemical findings in one of the sections showed it to be characteristic of schwannoma while the other section showed indications of idiopathic gingival enlargement. The patient has been followed up carefully and no recurrence has been noted.