Ancient schwannoma of the parapharynx causing dysphagia: a rare entity

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.

Ancient Schwannoma: Case Report of an Unusual Entity in an Unusual Oral Location

BACKGROUND Schwannoma is an uncommon benign tumor that develops from Schwann cells in the peripheral nervous system; 25-50% of such tumors occur in the head and neck. A rare variety of schwannoma, known as an ancient schwannoma, exhibits calcification, cystic degeneration, hemorrhage, myxoid stroma, pleomorphism, and nuclear hyperchromatism. Such characteristics may contribute to this tumor being incorrectly diagnosed as malignant. Almost all reported intra-oral ancient schwannomas behave innocuously. CASE REPORT A 20-year-old man presented to the oral surgery clinic with a right facial swelling that began a few months before. CT and MRI were performed and showed a well-defined cystic lesion anterior to the right masseter muscle, located in the subcutaneous area and measuring 28×24×20 mm. No extension to the surrounding tissues nor any other similar lesions were seen. Microscopic examination revealed an encapsulated nodular mass with cystic cavities, hemorrhage, and variably distributed myxoid and hyalinized stroma. The tumor demonstrated 2 distinct cell distributions: hypercellular areas (Antoni A) and myxoid hypocellular areas (Antoni B). Focal areas in high-power magnification showed atypical cells with hyperchromatic and pleomorphic nuclei. The tumor cells showed diffuse positivity for S-100 in IHC. The diagnosis of ancient schwannoma was made. At 1-year follow-up, there was no evidence of nerve injury or recurrence. CONCLUSIONS One more case of oral ancient schwannoma is added to the literature. This is the first reported in Saudi Arabia. It is prudent to be familiar with the degenerative and cytologic alterations of ancient schwannoma, as this may limit the likelihood of misdiagnosis and unnecessary treatment of this benign tumor, with an excellent prognosis.

Retrospective analysis of schwannoma in the oral and maxillofacial region: clinicopathological characteristics and specific pathology of ancient change

Schwannomas are benign tumours that originate from the Schwann cells of the nerve. Despite the frequency of their occurrence in the head and neck, data relating to their clinicopathological features in the region are limited. This study reviews the clinicopathological characteristics and specific pathology of ancient (degenerative) change in 40 cases in the oral and maxillofacial region. Medical records were reviewed of the 40 cases treated at Tokyo Medical and Dental University Hospital Faculty of Dentistry between 2000 and 2020. The most frequently involved site was the tongue, and the average tumour size was 13.2 mm. Degenerative changes were observed in eight cases. All tumours were completely excised through biopsy or local excision, and no recurrence was observed on clinical follow up. Statistical analyses revealed significant associations (p < 0.05) between ancient change and tumour size, and between ancient change and the apparent diffusion coefficient (ADC) value derived from diffusion-weighted magnetic resonance imaging (MRI). Analysis suggests that schwannoma progresses over a long period and subsequently undergoes secondary ancient changes. Pathological events such as cystic formation and haemorrhage that are associated with ancient changes, cause hypocellularity and lead to high ADC values. These values may indicate ancient change and should be considered when distinguishing schwannoma from other lesions.

Endoscopic Transoral Resection of Tongue Base Ancient Schwannoma

Schwannoma is a benign slow growing nerve sheath tumor that is typically encapsulated and composed of well-differentiated schwann cells. Schwannomas may take origin from different nerves such as cranial, spinal nerves, and the sympathetic chain. Approximately 25% to 45% of all occur in the head and neck only 1% of them are located in the oral cavity. However, it is quite rare to for schwannomas to form on the tongue base. Ancient schwannoma is the rarest, and also extremely rare in oropharynx. A 32-year-old female patient was admitted to our clinic with complaints of hoarseness, difficulty in swallowing, throat pain, snoring, and dyspnea. In examination, a smooth surfaced circumscribed mass, which originated from the tongue base was observed. In the magnetic resonance imaging, a 4.5 × 3 cm sized tongue base mass which narrowed the upper airway was detected. An endoscopic transoral excisional biopsy was performed. The histopathological diagnosis was determined as ancient schwannoma. The use of the endoscopic transoral approach can be suitable to protect the important anatomical structures, functions, and reduce the complications and esthetic concerns for the resection of tongue base schwannomas.

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.

Dysphagia caused by giant schwannoma of the supraglottic oropharynx: A case report and review of the literature

Background

Schwannomas are benign, encapsulated, peripheral nerve tumours that arise from the Schwann cell. Approximately 25%–45% of schwannomas occur in the head and neck. The most common site is the parapharyngeal space of the neck. However, schwannoma of the supraglottic oropharynx is rare.

Case presentation

We report on a 35-year-old female who complained of progressive dysphagia, from whom a large schwannoma in the supraglottic oropharynx was excised through a transoral approach. No recurrence was seen after one year follow-up.

Conclusion

Although rare, schwannomas do occasionally occur in the supraglottic oropharynx. When dysphagia is present, a thorough diagnostic procedure should be performed to evaluate the morphology and function of the upper aerodigestive tract. MRI is sensitive and specific in the diagnosis of schwannoma. And the best treatment of choice is complete excision with preservation of functions.

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Schwannoma is a benign peripheral nerve tumor that usually presents as a slow growing single lesion.

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Giant schwannoma of the supraglottic oropharynx is rare.

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The main symptom is dysphagia due to the location and mass of the tumor.

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MRI is particularly helpful in delineating schwannoma.

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Surgery is the treatment of choice.

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.

Intrapharyngeal schwannoma in a pediatric patient

Schwannomas are benign peripheral nerve neoplasms that arise from Schwann cells. They usually occur in the adult population. The most common site in the head and neck region is the parapharyngeal space. Intrapharyngeal schwannomas are extremely rare, and those that have been reported all occurred in adults. We report what to the best of our knowledge is the first case of an intrapharyngeal schwannoma in a pediatric patient. The patient, a 15-year-old boy, was treated successfully with surgical excision.