Palatal ancient schwannoma: optical, immunohistochemical and ultrastructural study with literature review

Clinical and radiological features of intracranial ancient schwannomas: a single-institution, retrospective analysis

Ancient schwannoma (AS) is a subtype of schwannoma characterized by slow progression despite degenerative changes in pathology. Although it is considered a benign tumor, most previous reports have focused on extracranial AS; therefore, the clinical characteristics of intracranial AS is not clear. We included 174 patients who underwent surgery for sporadic intracranial schwannoma, and 13 patients (7.5%) were diagnosed with AS. Cysts were significantly more common in patients with AS than conventional schwannomas (92.3% vs. 44.7%, p < 0.001), as was bleeding (38.5% vs. 6.9%, p = 0.003) and calcification (15.4% vs. 1.3%, p = 0.029). The maximum tumor diameter was also larger in patients with AS (35 mm vs. 29 mm, p = 0.017). The median duration from symptom onset to surgery (7.0 vs. 12.5 months, p = 0.740) did not significantly differ between groups, nor did the probability of postoperative recurrence (p = 0.949). Intracranial AS was strongly associated with cyst formation and exhibited a benign clinical course with a lower rate of recurrence and need for salvage treatment. Extracranial AS is reportedly characterized by a slow progression through a long-term clinical course, whereas intracranial AS did not progress slowly in our study and exhibited different clinical features to those reported for extracranial AS.

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.

Palatal Schwannoma: An Analysis of 45 Literature Reports and of an Illustrative Case

Introduction  Schwannomas are benign tumors originating from differentiated Schwann cells. Being the least common intraoral neoplasm of neural origin, it is rarely seen in the palate. The literature lacks an extensive review of intraoral schwannoma confined to the palate.

Objective  To review previously reported cases of palatal schwannoma along with an illustrative case, and to provide a better insight regarding clinicopathological and radiological features of this neural tumor in a rare intraoral site.

Data Synthesis  We present a case of palatal schwannoma in a 16-year-old female. An additional 45 cases were identified in 2 medical database searches (PubMed and Google Scholar) published from the year 1985 onwards, and from 13 countries, in the 5 continents. The ages of the patients ranged from 3 to 84 years old. Palatal schwannoma showed a slight predilection to females, with a male/female ratio of ∼ 1:1.81. Hard palate involvement is almost twice greater than soft palate involvement. Surgical excision was employed in almost all of the cases, and recurrence was reported only once.

Conclusion  Palatal schwannomas, although rare, have been reported both over the hard and the soft palate. They mostly present as a painless, firm, well-encapsulated, slow-growing solitary lesion over the lateral palatal aspect.

Imaging can add to suspicion and can delineate a differential diagnosis, but the diagnosis is confirmed by pathological examination. Fine-needle aspiration cytology (FNAC) is almost always inconclusive. Immunohistochemistry can assist in confirming a diagnosis, but is more important to rule out close differentials. Complete surgical excision is the treatment of choice, and recurrence or malignant transformation are extremely rare.

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.