Retrospective analysis of oral peripheral nerve sheath tumors in Brazilians

Lingual nerve revisited-A comprehensive review Part II: Surgery and radiology

The lingual nerve (LN) is a branch of the mandibular division of the fifth cranial nerve, the trigeminal nerve, arising in the infratemporal fossa. It provides sensory fibers to the mucous membranes of the floor of the mouth, the lingual gingiva, and the anterior two-thirds of the tongue. Although the LN should rarely be encountered during routine and basic oral surgical procedures in daily dental practice, its anatomical location occasionally poses the risk of iatrogenic injury. The purpose of this section is to consider this potential LN injury risk and to educate readers about the anatomy of this nerve and how to treat it.

Beyond Excision: Cryotherapy as a Non-surgical Treatment for Palatal Solitary Neurofibroma

Palatal solitary neurofibromas (SNFs), not linked to neurofibromatosis type 1, are uncommon. A 45-year-old female with a palatal SNF underwent non-surgical treatment using liquid nitrogen cryotherapy (LNC). The lesion, initially 9 x 8 x 3 mm, was treated with two 1-2 minute freeze-thaw cycles, progressively extended to two 2-2 minute freeze-thaw cycles to address the refractoriness. After four LNC sessions, the lesion resolved without recurrence at five months. This case demonstrates LNC's efficacy as a surgical alternative for palatal SNF, offering a non-invasive option for patients declining surgery. The positive outcome warrants further research into LNC's role in managing similar benign lesions.

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.

Clinicopathological study of malignant peripheral nerve sheath tumors in the head and neck: Case reports and review of literature

BACKGROUND

Malignant peripheral nerve sheath tumor (MPNST) is a rare and aggressive soft tissue sarcoma that poses a major diagnostic and therapeutic challenge.

CASE SUMMARY

We retrospectively reviewed patients with head and neck MPNSTs treated in our hospital from 2000 to 2021. The clinical features, pathological manifestations, treatments, and prognoses were summarized. We also reviewed the literature, focusing on MPNST in the mandible and maxilla. The study population consisted of five women and five men aged 22-75 years (mean age, 49 years). Of the 10 patients, 7 were initial cases and 3 were recurrent cases. All lesions were sporadic. The most common site was the mandible. The most frequently encountered symptoms were a progressive mass and local swelling. Complete or partial loss of trimethylation at lysine 27 of histone H3 (H3K27me3) was evident on staining in four of nine cases (one case was excluded due to lack of tissue for evaluation of loss of H3K27me3). The 2- and 5-year disease-specific survival rates were 86% and 43%, respectively. The average survival time was 64 mo.

CONCLUSION

MPNST is a highly malignant tumor with a poor prognosis, prone to a high risk of recurrence and distant metastasis. Complete surgical resection is the main treatment.

Trigeminal Traumatic Neuroma: a Comprehensive Review of the Literature Based On a Rare Case

PURPOSE OF REVIEW

Traumatic neuromas in general, and trigeminal traumatic neuromas in particular, are relatively rare entities originating from a damage to a corresponding nerve or its branches. This manuscript is a comprehensive review of the literature on trigeminal traumatic neuromas based on an interesting and challenging case of bilateral intraoral lesions.

RECENT FINDINGS

The diagnosis for this patient was bilateral trigeminal traumatic neuromas. It is possible that these patients have a genetic predisposition to the development of these lesions. It is a neuropathic pain condition and may mimic dental and other trigeminal pain entities. Topical treatment with lidocaine gel, utilizing a custom-made neurosensory stent, rendered the patient significant and sustained pain relief. Trigeminal traumatic neuromas present a diagnostic challenge even to a seasoned clinician, due to the complex clinical features that may mimic other entities. Topical medications such as local anesthetics may be a good viable alternative to systemic medications to manage the pain associated with the condition. Early identification of the lesion and the associated pain helps in the succinct management of symptomatic trigeminal traumatic neuromas.

Palisaded encapsulated neuroma in tongue - A commonly misdiagnosed peripheral nerve sheath tumor

Palisaded encapsulated (solitary circumscribed) neuromas are benign neural tumors, rarely found in oral mucosa. This case reports a 24-year-old man that presented a unique soft nodule at the left side of the tongue. An excisional biopsy was performed under local anesthesia and histopathological examination of the surgical specimen revealed a well circumscribed mass composed of spindled Schwann cells, often aligned and fasciculated, forming occasional nodules embedded in a fibrous stroma. Histopathological analysis showed the presence of positive cells for S-100, EMA, CD57, and collagen IV. Based on clinical and microscopical features, the diagnosis established was of palisaded encapsulated neuroma. This case report aims to discuss the differential diagnosis among palisaded encapsulated neuroma and the other neural tumors that affect the oral mucosa.

Immunoexpression of BDNF, TrkB, and p75NTR receptors in peripheral neural lesions of the head and neck

BACKGROUND

Brain-derived neurotrophic factor (BDNF) and neurotrophin receptors have been recognized as fundamental regulators of normal brain development, homeostasis, and plasticity. They have also been studied in the behavior of central nervous system tumors. Here, we studied the pattern of BDNF, TrkB and p75NTR immunoexpression in peripheral benign and malignant neural lesions in head and neck.

METHODS

This cross-sectional analytical study included 79 cases of head and neck neural lesions. Nineteen cases of traumatic neuromas (TN), 20 cases of granular cell tumors (GCT), 16 cases of neurofibromas (NF), 20 cases of schwannomas (SC), and 4 malignant peripheral nerve sheath tumor (MPNST) were submitted to immunohistochemistry with BDNF, TrkB, and p75NTR antibodies. A semi-quantitative analysis was performed.

RESULTS

The analysis of BDNF demonstrated a high percentage of positive cells in TN, GCT and SC with a decrease in cases of NF and MPNST. TrkB presented a lower significant immunoexpression in GCT in relation to the TN, NF, SC, and MPNST (P < .0001); and TN showed less percentage of positive cell compared to SC (P = .0017). Regarding p75NTR, the percentage of positive cell was significantly reduced in MPNST compared GCT (P = .009), NF (P = .0138) and SC (P = .0069). Also, a decrease in TN compared to GCT (P = .007) was observed.

CONCLUSIONS

Our results showed the immunoreactivity of BDNF, TrkB, and p75NTR in head and neck peripheral neural lesions. Reduction of BDNF and p75NTR in MPNST might suggest down-regulation during the acquisition of malignant phenotype.

Unusual exophytic gingival lesion in a newborn treated with diode laser

Gingival lesions rarely occur in newborns. However, when present, they commonly worry the parents and impair the infant's feeding, thus affecting growth. Such lesions are usually nonneoplastic in nature, although malignancies may develop; therefore, specimens must be submitted for histopathologic examination. A 2-month-old girl presented with a 10-mm nodule on the anterior lower alveolar ridge in association with natal tooth extraction and neonatal tooth eruption. The lesion was excised with high-power laser under local anesthesia, and a histopathologic diagnosis of a peripheral ossifying fibroma was made. In addition to peripheral ossifying fibromas being rare in newborns, the use of high-power lasers for surgical procedures in newborns have been proven to be safe, comfortable, and efficient.

Tongue Schwannoma: A Clinicopathologic Study of 19 Cases

Schwannomas commonly occur in the head and neck but infrequently involve the oral cavity and rarely affect the tongue. The clinical and pathologic features of 19 cases of schwannoma arising in the tongue were analyzed. There were 13 males and 6 females ranging in age from 12 to 82 years (mean 34 years; median 29 years). The majority of tumors presented as an asymptomatic mass localized to the anterior two-thirds of the tongue. Histologically, 18 schwannomas exhibited characteristic Antoni A and B areas with the former pattern predominating. One tumor was composed exclusively of cellular Antoni A tissue and was classified as a cellular schwannoma. Tumor encapsulation was variable with nearly half of the lesions lacking a well-defined fibrous capsule. All were strongly and diffusely positive for S-100 protein. No recurrences were observed on clinical follow-up. Schwannoma of the tongue, although rare, should be separated from other types of lingual nerve sheath proliferations and tumors.

Solitary neurofibroma of the floor of the mouth: rare localization at lingual nerve with intraoral excision

Background

Neurofibromas (NF) are benign tumors of the peripheral nerves that are composed of Schwann cells, perineural-like cells and fibroblasts. The differential diagnosis for a solitary intraneural variant of neurofibroma arising in the floor of the mouth is broad and includes a submandibular gland neoplasm and adenopathy, among others. The intraoral approach is the best choice for a medium-sized lesion.

Case presentation

We report a rare case of a solitary neurofibroma of the floor of the mouth in a 31-year-old male. The patient consulted the dental emergency department for acute pain of the left mandible. Systematic clinical examination revealed the presence of a mass in the left mouth floor. The panoramic x-ray was not conclusive and the magnetic resonance imaging (MRI) revealed a well-defined soft tissue lesion with homogenous isosignal intensity on the T1-weighted image, high intensity signal on the T2-weighted image and heterogeneous enhancement following contrast-enhancement on the T1-weighted Fast Sat image. The surgical excision of the soft-tissue neoplasm was accomplished by an intraoral approach. The specimen was sent for histopathologic analysis and Immunohistochemical studies which confirmed the diagnosis of a myxoid predominant intraneural solitary neurofibroma.

Conclusion

The diagnosis of neurofibroma was confirmed by histopathological evaluation and immunohistochemical studies which also excluded other entities in the histopathologic differential diagnosis including schwannoma and a malignant peripheral nerve sheath tumor among other. Localized (solitary) neurofibromas most often occur as sporadic lesions, however; diagnosis of a solitary neurofibroma prompts clinical evaluation to exclude the remote possibility of neurofibromatosis. The purpose of this case report is to raise awareness of the uncommon presentation of neurofibroma and to document the successful management of such a lesion using an intraoral 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.

Sporadic Neurofibroma of the Tongue Unassociated with Neurofibromatosis Type I: A Clinicopathologic Study of Ten Cases

Neurofibromas rarely occur within the oral cavity and infrequently involve the tongue. The majority of lingual neurofibromas arise in patients affected by neurofibromatosis type 1 (NF1). Neurofibromas of the tongue unassociated with this disorder are exceedingly uncommon. The clinical and pathologic features of 10 cases of sporadic lingual neurofibromas, unassociated with NF1, were evaluated. The patients included six females and four males ranging in age from 30 to 69 years (mean 59 years; median 63 years). An asymptomatic or slowly enlarging lingual mass was the most common clinical presentation. None of the patients were documented to have NF1. Histologically, the tumors were unencapsulated and situated beneath an intact squamous mucosa. The tumors are comprised of spindle cells with wavy nuclei within a collagenous to myxoid stroma. One tumor was characterized by a plexiform growth pattern. The lesional cells were positive for S-100 protein. Clinical follow up, available for all patients, showed no recurrences and no subsequent development of additional clinical manifestations of NF1. Lingual neurofibromas should be distinguished from other peripheral nerve sheath tumors that can affect this anatomic site. This series of cases confirms that sporadic neurofibromas of the tongue may be rarely encountered in patients having no other features of NF1.

Demographic, Clinical and Histopathological Features of Oral Neural Neoplasms: A Retrospective Study

Intraoral neural neoplasms though unusual may be clinically significant. The aim of this study was to categorize and evaluate oral neural tumors in a large oral pathology biopsy service. With IRB approval, a retrospective search of all neural neoplasms of the oral cavity in the archives of the University of Florida Oral Pathology Biopsy Service spanning from 1994 to 2015 was performed. Extraoral cases as well as cases with insufficient patient information were excluded. A total of 340 out of 164,578 submitted specimens in a 22 year period (0.2%) were included with a mean age of 43.3 years (range: 6-89), and 44% male and 56% female. The most commonly affected locations were: tongue (37.5%), palate (22%), lip (19%), and gingiva (14%). The microscopic diagnoses rendered, in descending order of frequency were: neurofibromas (NFs): 123 (36%), granular cell tumor (GCT): 108 (32%), schwannomas: 61 (17%), palisaded encapsulated neuromas: 39 (11%), benign neural lesion not otherwise specified: 8 (2%), and mucosal neuroma c/w multiple endocrine neoplasia type 2B (MEN 2B): 1 (< 0.5%). Six cases of NF reported a history of neurofibromatosis Type 1 (NF 1). Four cases showed multifocal lesions. Immunohistochemical staining was performed on equivocal cases (25% of the lesions) and all were confirmed by their S-100 positivity. Intraoral neural neoplasms, though uncommon should be in the differential diagnosis of oral soft tissue entities and specific consideration to syndromal linkage is paramount as this may impact patient management.

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.

Neurogenic tumors and tumor-like lesions of the oral and maxillofacial region: A clinicopathological study

Objective

Oral and maxillofacial lesions of neural origin are rare soft tissue neoplasms. The aim of the present study is to review the epidemiological data of oral and maxillofacial neurogenic lesions submitted for diagnosis to our laboratory over a 31-year period (August 1984–March 2015).

Materials and methods

The available formalin-fixed embedded specimens, Hematoxylin and Eosin slides, demographic and clinical data were retrieved.

Results

Thirty-one cases were included in this study, representing 0.6% of the 5161 biopsies submitted. Most of the diagnosed cases 11 (35.5%) were traumatic neuromas. The other cases included 2 (6.5%) solitary circumscribed neuromas, 2 (6.5%) melanotic neuroectodermal tumors of infancy, 2 (6.5%) Schwannomas, 5 (16.1%) granular cell tumors, and 9 (29%) neurofibromas. The patients’ ages ranged from 5 months to 78 years. Among these cases, 16 were males (51.61%) and 15 were females (48.38%).

Conclusion

This analysis showed that neural lesions affecting the oral and maxillofacial region were rare and mostly benign in nature. Such lesions should be carefully diagnosed because of their association with life-threatening syndromes and the possibility of malignant transformation.

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.

Lingual neurofibroma causing dysaesthesia of the tongue

Neurofibroma is a benign tumour derived from the neural sheaths of peripheral nerves and composed of Schwann cells, fibroblast-like cells and intermediate cells. The usual clinical presentation of an oral neurofibroma is swelling. A 62-year-old woman was referred to our department of otorhinolaryngology with irritation and dysaesthesia of the lateral aspect of the tongue. The only finding was a slightly red area from which a biopsy was taken. The macroscopic findings observed by the surgeon were consistent with normal tongue tissue. The histopathological examination showed a small, rounded tumour closely approximated to an invagination of the surface epithelium and with a small lymphatic infiltrate. The tumour was a neurofibroma. A Schwannoma type B was considered but the presence of small nerves and positive neurofilament reaction favoured a neurofibroma. The patient had no other neurofibromas or skin lesions. At a 3-week follow-up visit all symptoms had resolved.

Intraoral Schwannomas: Presentation of a series of 12 cases

Introduction: Schwannomas are benign and not very frequent tumors of the peripheral nerves, derived from the nerve supporting Schwann cells. Study Design: Data were collected on the clinical manifestations (sex, age), location, size and symptonts of the lesions as well as the evolution time and the initial (presumption) diagnosis. Results: Twelve patients were documented, with a mean age of 29,5 ± 12,1 years (range 16-50) and a balanced gender distribution. The mean duration of the lesions was 42,17± 45,3 months. The lesion located in the floor of the mouth was the largest tumor, measuring about 4 cm in maximum diameter, while the average size of the 12 schwannomas was 2.04± 1.1 cm. Conclusion: We present 12 oral schwannomas diagnosed and treated over a period of 10 years.

Key words:Schwannomas, oral benign tumor, neurilemmoma.

Solitary myxoid neurofibroma of the soft palate

The neurofibroma is a benign tumor of neural origin, not frequently located in the oral cavity, and, especially, extremely rare in the soft palate. When it occurs solitarily, it is a spontaneous tumor without any internal manifestations. We report a case of an isolated neurofibroma of the soft palate not associated with von Recklinghausen disease.

Clinicopathologic analysis of 7 cases of oral schwannoma and review of the literature

Schwannomas, also known as neurilemmomas, are uncommon neoplasms apparently derived from Schwann cells. The growth of these tumors causes displacement and compression of the nerve of origin. Schwannomas are usually solitary lesions but can be multiple when associated with neurofibromatosis. Anti-S100 protein is the most widely used antibody for the identification of this neoplasm. Surgical excision is the treatment of choice for schwannomas, with few and controversial reports of recurrence or malignant transformation. The present article reports 7 additional cases of oral schwannoma, and the literature is reviewed regarding clinicopathologic features, immunohistochemical findings, differential diagnosis, and therapeutic management of this benign neural tumor.

A 38-year review of oral schwannomas and neurofibromas in a Brazilian population: clinical, histopathological and immunohistochemical study

The benign peripheral nerve sheath tumours are rare lesions mainly represented by schwannoma and neurofibroma. The present work evaluated the clinical and histopathological features of schwannomas and neurofibromas of the oral cavity diagnosed in a Brazilian population. Among 9.000 cases of oral lesions archived from 1970 to 2008, four schwannomas and 12 neurofibromas were identified, microscopically revised and immunohistochemically certified through a panel including monoclonal antibodies (anti-S100, vimentin, HHF-35 and desmin). From biopsy and histological sections records, clinical and histopathological data were retrieved, reviewed and statistically analysed. Predominantly, schwannomas affected non-white males (3:1), with an age and size averages of 34.7 years and 2.8 cm, respectively. Neurofibromas preferentially occurred on the gingival/alveolar ridge of white females (5:1), with 35.7-year mean age, peak of incidence between 3rd and 5th decade, and size average of 1.7 cm. (12 cases, 75%). The studied tumours exhibited more frequently as a painless, sessile and slow growth very similar to other oral lesions, but their microscopic features differed significantly. Schwannomas and neurofibromas are extremely uncommon in the oral cavity, exhibiting clinical features very similar but specific and peculiar microscopic findings that are useful in the establishment of the diagnosis, which in some particular cases must be confirmed by immunohistochemistry.