A Rare Finding of Schwannoma of the Vidian Canal: A Case Report

Paranasal Schwannomas: A Comprehensive Study of 2 Cases

Paranasal sinus tumors are a heterogeneous group of neoplasms (with paranasal schwannomas being a rare subtype) that are often present with non-specific symptoms, such as nasal obstruction and epistaxis. Thus, early diagnosis is crucial for optimal management. This study presents 2 cases of paranasal schwannomas, detailing their clinical presentation, diagnostic methods, and treatment approaches. Both patients underwent endoscopic sinus surgery with successful tumor excision and had no significant complications or recurrences during follow-up. Diagnosis was based on a combination of clinical examination, radiological imaging (computed tomography and magnetic resonance imaging), and histopathological confirmation with immunohistochemical staining. Treatment consisted primarily of endonasal resection, with consideration of frontal craniotomy if necessary. This study aims to contribute to the understanding of paranasal schwannomas and emphasizes the importance of early detection and treatment to improve patient outcomes.

Vidian nerve neurofibroma

Vidian nerve is created from the connection of the greater petrosal nerve and the deep petrosal nerve (Giraddi et al., 2010). These two nerves transmit parasympathetic and sympathetic fibers respectively. Vidian nerve tumour is one of the rarest known tumours (Hong et al., 2014). Genetic changes effectively play a role in the development of nerve sheath tumors. Of course, due to the rarity of this type of tumor, there is not much information about its causes and risk factors (Yamasaki et al., 2015). The incidence rate of malignant peripheral nerve sheath tumors is about 0.001 % (Fortes et al., 2019). Considering the low prevalence of this tumor and the type of treatment performed on this patient, the investigation of the case presented in this study can lead to a better understanding and more correct treatment. This case report has been proposed due to the very low prevalence of neurofibroma of the Vidian nerve in the world. Vidian nerve supplies sympathetic and parasympathetic fibers to the lacrimal glands and nasopalatine mucosa. In many cases, involvement of the Vidian nerve by neurofibroma can be misleading for doctors. Due to the very low prevalence of neurofibroma of the Vidin nerve, the possibility of its being missed and not diagnosed during the examination of patients by doctors is very high. This case report is presented in order to familiarize scientists with this lesion due to its very low prevalence. This therapeutic approach that was used in this case requires longer follow-up periods, but it can prevent possible complications after surgery.

Endoscopic Endonasal Surgery of a Large Vidian Nerve Schwannoma With Preparation for Avoiding Major Vascular Injury

Vidian nerve schwannomas are extremely rare, and their surgical management requires an awareness of the surrounding vascular and nervous systems, including the internal carotid artery. Herein, we report a case of a vidian nerve schwannoma that was successfully removed using an endoscopic endonasal approach in a 21-year-old patient who presented with lacrimal hyposecretion. Imaging revealed a large mass extending to the middle cranial fossa posteriorly, to the pterygopalatine fossa laterally, and to the sphenoid sinus medially. The paraclival and petrosal portions of the internal carotid artery were displaced posteriorly. Endoscopic observation of the right nose demonstrated anterior displacement of the inferior portion of the middle turbinate. Based on the above, we suspected a vidian nerve schwannoma, and endoscopic endonasal surgery was performed with particular attention to avoid vascular injuries. An endoscopic transmaxillary approach was used to expose the anterior surface of the tumor. After confirming the pathological diagnosis intraoperatively, intracapsular resection of the tumor was completed using an ultrasonic surgical aspirator with Doppler monitoring of the location of the internal carotid artery. Endoscopic management of the surgical field and preparation to avoid vascular injury are essential for safe and efficient tumor resection.

Vidian Nerve Schwannoma: A Rare Skull-Base Neoplasm Presenting with Ocular Manifestations: A Case Report and Literature Review

INTRODUCTION

Vidian nerve schwannomas are exceedingly rare, with only 7 cases reported since 2006. Patients presenting with ocular symptoms have been reported in only 1 case.

CASE PRESENTATION

A 54-year-old woman presented with a 3-month history of right periorbital pressure, third cranial nerve palsy, and visual field defect. Imaging results showed a right sphenoid skull-base mass with obliteration of the vidian canal that extended into the pterygopalatine fossa. The patient underwent an extended endoscopic resection with pterygopalatine fossa dissection. Pathologic findings demonstrated a schwannoma.

DISCUSSION

A literature review showed that this is the second reported case of a vidian nerve schwannoma presenting with ocular symptoms and that endoscopic resections are becoming the standard of care. Practitioners should be aware that vidian nerve schwannomas can present as a skull-base mass with predominantly ocular symptoms, including vision loss, secondary to mass effect. Consideration should be given to this entity in the setting of typical radiographic and histopathologic characteristics. Endoscopic approaches to resection are safe and have low morbidity.

Visualization of the vidian canal and nerve using magnetic resonance imaging

BACKGROUND AND PURPOSE

Few studies have investigated the vidian nerve (VN) and vidian canal (VC) with the use of magnetic resonance imaging (MRI). The present study aimed to characterize the VC and VN using MRI.

MATERIALS AND METHODS

A total of 91 patients underwent thin-sliced, contrast MRI. The course of the VC and VN and the relationships with relevant structures were analyzed.

RESULTS

The VC was identified in 95% of axial images on the right side and in 93% on the left. The course of the VC was delineated in 99% of serial coronal images on both sides. The VN location in the VC was highly variable. The course of the VC and transmitting VN was delineated in 95% of sagittal images on the right side and in 91% on the left. The mean length of the VC was 19.8 mm on the right side and 19.3 mm on the left. Topographical relationships between the anterior genu of the petrous internal carotid artery and the posterior end of the vidian canal could be classified into three types. Of these, the type terminating at the level of the petrous carotid was the most predominant, comprising 76% of 182 sides. The course of the VC and transmitting VN could be classified into four types. The straight type was the most predominant and was found in 41%.

CONCLUSIONS

The VC and transmitting VN are structures with variable morphologies. Contrast MRI is useful for delineating the VC and VN.