Ancient neurilemmoma: A rare oral tumor

Hyalinization as a histomorphological risk predictor in oral pathological lesions

Background

Hyalinization is a process of conversion of stromal connective tissue into a homogeneous, acellular translucent material. Nevertheless, hyalinization could provide insights into the biologic behaviour and prognosis of pathological lesions. Few studies with limited sample size have intended to assess the correlation of hyalinization and biologic behaviour in oral lesions.

Aim

The current review aims to comprehensively appraise the mechanism of hyalinization in pathological oral hyalinizing lesions (OHL) and its clinical implications with emphasis on differential stains employed.

Methods

An electronic search was performed in the PubMed database (from year 2000-2020) using the keywords "special stains in oral hyalinizing lesions", "significance of hyalinization in oral lesions" and "hyalinization and biologic behaviour". Original research articles analyzing the effect of hyalinization on biologic characteristics of the lesion were evaluated in this review. Narrative review articles that provided insights into the mechanism of hyalinization and maturity of collagen fibers were also considered for analysis.

Conclusion

The presence of hyalinization does seem to have a significant effect on the biologic behaviour of pathological lesions. There is substantial scope to further investigate the process of hyalinization on larger samples and its correlation with the aggressive behaviour of OHLs. Special stains and advanced investigations such as immunohistochemistry for stromal markers would define the nature of hyalinized material and validate the correlation.

Clinical significance

The prediction of the biologic behaviour of a lesion established through assessment of hyalinization would prevent unwanted over or under treatment leading to a better prognosis.

Malignant peripheral nerve sheath tumor: A rare malignancy

Malignant peripheral nerve sheath tumor (MPNST) is also termed as spindle cell malignancy of the peripheral nerve Schwann cell. It is a rare and highly aggressive, soft-tissue sarcoma of ectomesenchymal origin that accounts for 10% of all sarcomas and only 10%–12% of all lesions occur in the head-and-neck region, thus making it a rare entity. It arises de novo or from the preexisting benign neurofibroma. The diagnosis of MPNST is one of the most elusive among the soft-tissue tumors because of its greater variability in overall presentation both clinically and histologically. This difficulty can be overcome by the use of immunohistochemistry. This article presents a rare case of MPNST of the oral cavity in a 40-year-old female patient with a brief review of the current literature.

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.

Neurilemmoma of Maxillary Alveolus: A Rare Case Report and Review of Literature

Schwannomas or neurilemmomas are benign, slow growing, usually solitary and encapsulated tumor, originating from Schwann cells of the nerve sheath. Intraoral schwannomas account for 1% of head and neck region and are commonly seen at the base of the tongue. Most of the literature, reports of schwannomas in the tongue region are common. In this article we report a rare occurrence of schwannoma in the maxillary alveolus region and its management. A 45 year old female patient reported to the department of oral and maxillofacial surgery with a complaint of swelling in the left maxillary alveolus in relation to molar teeth that had been present for more than 3 months. Apparently the swelling was small one initially, which gradually increased in size. Such a rare cas e of intraoral schwannoma should be followed up periodically to look for any malignant transformation and recurrences. An important conclusion that has evolved from the reviewed articles, is that the differential diagnosis of painless nodules in head and neck must include schwannomas.

Ancient schwannoma of gingiva - A rare case report

Oral schwannomas (OSs) are rare benign tumors of oral cavity derived from peripheral nerve sheath, composed of proliferation of schwann cells in a characteristic pattern. AS are long-standing lesions which exhibit degenerative changes and atypia due to which they could be mistaken for malignancy. The mean age of occurrence of AS in oral cavity is 43 years, and no case of oral AS has been reported in a pediatric patient so far. Here, we present a rare case of AS of oral cavity in a 10-year-old male child.

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.

Recurrent Ancient Intraosseous Neurilemmoma of Maxilla: A Rare Case Report

Neurilemmomas are benign tumors of peripheral nerve sheath Schwann cells. One of the variants of neurilemmoma is the ancient type of neurilemmoma characterized by degenerative features such as cystic degeneration, calcification, hemorrhage and hyalinization which could be easily misdiagnosed. Their occurrence in oral cavity is extremely rare and intraosseous type occurring in maxilla is exceedingly rare with very few cases being published in literature. A 38 year old male patient reported with a chief complaint of swelling over the left cheek and left upper back region since 10 months. The case is of recurrent intraosseous ancient neurilemmoma in the maxilla in the patient which is distinctive for the lesion. This unique case presented with distinct histologic architectural pattern of ancient neurilemmoma showing degenerative changes such as cystic degeneration and recurred within a short duration of time.

Neurilemmoma of Retromolar Region in the Oral Cavity

Neurilemmoma also known as schwannoma is benign nerve sheath tumor rarely occurring in the oral cavity. Only 1% of all extracranial schwannomas show that intraoral occurrence with tongue is the commonest site and retromolar region is the least common site. It presents as encapsulated, slow growing, solitary, smooth-surfaced, usually asymptomatic tumor. We report a case of 70-year-old male with well-defined mass on left retromolar region which was painless and slow growing. Diagnosis is made by histological examination and immunohistochemistry analysis to confirm the neural tissue origin of the lesion. The treatment is complete surgical excision of the lesion without recurrence.