Neurofibroma of the vagus nerve in the head and neck: a case report

Isolated neurofibromas of the great auricular nerve: A rare localization in a pediatric patient with neurofibromatosis type-1

Peripheral nerve sheath tumors encompass a spectrum of well-defined clinicopathologic entities, ranging from benign tumors, such as neurofibromas, to high grade malignant neoplasms termed malignant peripheral nerve sheath tumors. Morphologic variability of these tumors is wide, and they engender some of the most controversial, difficult differential diagnoses. Localized neurofibromas often involve a major nerve and result typically in fusiform expansion of the nerve trunk (intraneural subtype). We report a case of circumscribed solitary neurofibromas in a 14-year-old boy with NF1 who presented to our department with a left neck swelling. The neurofibromas lesion involved the anterior branch of the great auricular nerve. The sensory symptoms initially reported by the patient (paresthesia and hyperesthesia) in the lower preauricular region. Surgical treatment represents the therapeutic method of choice in the approach to neurofibromas, considering functional disorders and possible aesthetic deformities. The case described presented difficulties in surgical excision, based on risk of functional and aesthetic results.

Large Cervical Vagus Nerve Tumor in a Patient with Neurofibromatosis Type 1 Treated with Gross Total Resection: Case Report and Review of the Literature

Neurofibromas are benign peripheral nerve sheath tumors that occur commonly in individuals with neurocutaneous disorders such as neurofibromatosis type 1. Vagal nerve neurofibromas, however, are a relatively rare occurrence. We present the case of a 22-year-old man with neurofibromatosis type 1 with a neurofibroma of the left cervical vagal nerve. The mass was resected through an anterior approach without major event. In the postoperative course, the patient developed left vocal cord paralysis treated with medialization with injectable gel. We then present a comprehensive review of the literature for surgical resection of vagal nerve neurofibromas.

CT and MRI evaluation of nerve sheath tumors of the cervical vagus nerve

OBJECTIVE

Nerve sheath tumors arising from the cervical vagus are rare. The purpose of this study was to evaluate the role of CT and MRI in the diagnosis of these uncommon neoplasms.

MATERIALS AND METHODS

The CT and MR studies and clinical data of 11 patients with surgicopathologic evidence of a nerve sheath tumor of the cervical vagus (nine schwannomas [including two ancient schwannomas] and two neurofibromas) who had been referred to our institute from January 1999 through 2009 were retrospectively reviewed. The tumors were evaluated with respect to their location, number, morphology, attenuation and/or signal intensity, enhancement characteristics, and patterns of mass effect.

RESULTS

The tumors were solitary and well circumscribed. On CT, eight tumors were hypodense with poor enhancement, two were predominantly isodense, and a single lesion had multiple cystic areas with enhancing solid components. On MRI, they were heterogeneously bright on T2-weighted images with intense, inhomogeneous postgadolinium enhancement. The "split fat" sign, "entering and exiting nerve" sign, "fascicular" sign, and "hyperintense rim" sign were seen in some patients. The internal or common carotid artery was displaced anteriorly in eight patients, maintained a neutral position in two patients, and was displaced posterolaterally in another patient. In all patients except two, the tumor separated the carotid artery from the internal jugular vein. Vagal schwannomas splayed the carotid bifurcation in three patients.

CONCLUSION

In conclusion, we present the patterns of mass effect and a spectrum of CT and MRI characteristics of nerve sheath tumor of the cervical vagus including observations that are sparingly described in the published literature.

Sporadic and multiple neurofibromas in the head and neck region: a retrospective study of 33 years

The neurofibroma occurs as isolated or multiple lesions frequently associated with neurofibromatosis type 1 (NF-1). The aim of this study was to analyze the clinical and histopathological features of neurofibromas, particularly the plexiform variant, in the skin and oral mucosa, discussing their pathogenesis as well as clinical management of isolated lesion unassociated with NF1. The clinicopathologic features of 66 neurofibromas in the head and neck region diagnosed at the pathology laboratories of the Bauru Dentistry School and Lauro de Souza Lima Research Institute from 1970 to 2003 were reviewed. The clinical data, therapy, and follow-up information were obtained from the medical records. The results showed a high frequency of cutaneous lesions (81.8%) occurring mainly in females older than 40 years. Isolated neurofibromas were found in 51.2% of patients, and multiple lesions were often associated with the NF-1. The histopathological analysis demonstrated that diffused neurofibromas occur more frequently than the plexiform type. However, one case of plexiform neurofibroma was detected in the oral mucosa as an isolated lesion non-associated with the NF-1. The indolent clinical behavior of isolated neurofibromas in the head and neck region and the absence of NF-1 association reinforce that sporadic lesion could be hyperplastic or hamartomatous rather than neoplastic in nature.

Concomitant Vagal Neurofibroma and Aplasia of the Internal Carotid Artery in Neurofibromatosis Type 1

We report the case of a patient with neurofibromatosis type 1 who had both aplasia of an internal carotid artery (ICA) and a vagal neurofibroma. To our knowledge, this is the first report in the literature of the simultaneous presence of these two rare disorders in a single patient. We believe that this is also the first report of an absence of an ICA in a patient with neurofibromatosis type 1. The patient was a 19-year-old woman who complained of a slowly growing neck mass. The mass occupied the right parapharyngeal space and upper cervical region. The patient had no other masses on physical examination, but widespread café au lait spots were evident. This led us to suspect the presence of a vagal neurofibroma. The tumor was removed, and pathology confirmed the diagnosis. No intracranial aneurysms were detected on cerebral angiography.

Neurogenic tumors of the cervical vagus nerve: report of four cases and review of the literature

OBJECTIVE AND IMPORTANCE

Nerve sheath tumors arising from the cervical vagus nerve are extremely rare. These tumors most often present as asymptomatic, slowly enlarging, lateral neck masses and therefore often come initially to the attention of otolaryngologists and general surgeons. Because they are nerve tumors, however, neurosurgeons must be able to recognize and treat these rare entities. We report three cases of schwannoma and one case of neurofibroma of the cervical vagus nerve that were encountered at our center (Louisiana State University Medical Center) during a 31-year period.

CLINICAL PRESENTATION

The patients ranged from 31 to 61 years of age at the time of presentation to Louisiana State University Medical Center. Presenting complaints included hoarseness, Horner's syndrome, and palpation of an enlarging, asymptomatic, cervical mass. Reviews of systems revealed episodes of aspiration for one patient and frequent respiratory illnesses for two patients. These episodes were possibly related to their tumors. Imaging studies demonstrated well-circumscribed masses in the region of the carotid sheath.

INTERVENTION

Using microsurgical techniques, gross total resection of all four tumors was accomplished. For one patient, the vagus nerve needed to be divided and an end-to-end anastomosis was performed. For the other three patients, resection of the tumor was achieved with the vagus nerve in continuity.

CONCLUSION

Vagal nerve schwannomas and neurofibromas in the neck are rare neoplasms. We present four cases of these benign tumors. The pathological features, epidemiological characteristics, presentation, differential diagnosis, and management are discussed. Gross total resection with preservation of the vagus nerve remains the treatment of choice.

Vagus nerve imaging with ultrasound: anatomic and in vivo validation

To provide the anatomic basis and demonstrate the reproducibility of ultrasound studies for the identification of the vagus nerve within its course in the carotid sheath in the neck, cadaveric and in vivo imaging studies were conducted. On transverse B-mode images of the neck, there is a centrally hypoechoic and peripherally hyperechoic structure between the common carotid artery and the jugular vein inside the carotid sheath. This structure was also identified in a fresh, nonpreserved cadaver and was marked with a hypodermic needle by means of a transdermal approach. Neck dissection was performed leaving the carotid sheath intact. B-mode imaging yielded detailed anatomic information about the structures in the carotid sheath. Further dissection showed the vagus nerve as the target of the needle. One hundred consecutive transverse carotid scans were reviewed, and the characteristic echo patterns of the vagus nerve were identified in 97 instances. A distinct and reproducible, round, hypoechoic structure was defined adjacent to the common carotid artery and jugular vein as the vagus nerve. On the basis of this study, a new, noninvasive, and highly reproducible method to locate the vagus nerve in the carotid sheath is introduced. This may lead to further clinical application such as presurgical localization or ultrasound-guided needle studies. Stimulation of the vagus nerve has been proposed for seizure therapy. The diagnosis of vagus nerve tumors may be improved.