Plexiform neurofibroma of the cervical portion of the vagus nerve

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.

Cavernous hemangioma of infrahyoid carotid sheath and review of the literature on carotid sheath tumors

BACKGROUND

Carotid sheath may include a variety of lesions such as neurogenic or vascular, tumors originating from extra-adrenal chromaphil cells, squamous cell carcinomas, and lymphomas. Hemangiomas are benign congenital neoplasms, which, when located in the head and neck region, may be easily misdiagnosed due to their infrequent localization.

METHODS AND RESULTS

We report an unusual case of cavernous hemangioma of the infrahyoid carotid sheath presenting as palpable mass in a 51-year-old woman with no prior medical history. A review of the literature was performed to investigate the radiological and histopathological characteristics and highlight the treatment of carotid sheath lesions.

CONCLUSIONS

CT, MRI, and MR angiography would help to locate hemangiomas of carotid sheath, but only surgical excision and histopathology can reveal their true 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.

Ultrasonographic imaging of the vagosympathetic trunk in the dog

The purpose of this study was to evaluate the applicability of ultrasonographic imaging of the vagosympathetic trunk in the dog. Cervical ultrasound was performed in 30 healthy dogs. In all 30 dogs the vagosympathetic trunk was detected as a hypoechoic structure in the carotid sheath, adhering the dorsomedial surface of the common carotid artery. The echotexture of the nerve was heterogeneous with anechoic areas separated by hypoechoic bands. A scanner equipped with a 5 to 8 MHz linear array probe was used for imaging and measurements. The diameter of the vagosympathetic trunk ranged from 0.59 to 2.48 mm varying in correlation to the body weight. In summary, ultrasonography is a helpful noninvasive method to image and evaluate the cervical vagosympathetic trunk in the dog.

Sonography of the cervical vagus nerve: normal appearance and abnormal findings

OBJECTIVE

The purpose of this study was to assess the appearance of the cervical vagus nerve in healthy individuals and to investigate the potential role of sonography in revealing neck masses that cause vagal dysfunction.

SUBJECTS AND METHODS

We examined 150 consecutive patients. In 144 patients the presence of thyroid, salivary gland, or lymph node disease was suspected. In three patients a cervical mass was palpable, and three patients had symptoms of dysfunction of the inferior laryngeal or vagal nerves. The pathologic diagnoses of the masses were obtained at biopsy.

RESULTS

In 144 individuals the normal vagus nerve was recognized on each side of the neck as a thin band that occupied the posterior angle formed by the common carotid artery and the internal jugular vein. Three patients had tumors arising from the vagus nerve: one neurofibroma, one neurinoma, and one chemodectoma. These tumors were located in the neurovascular bundle and posterior to the vessels; their origin from the vagus nerve was clearly visible in all patients because of the contiguity of the mass with the nerve bundle. In the other three patients, sonography revealed an extrinsic mass that compressed and displaced the vagus nerve out of its longitudinal axis; two cases were hyperplastic nodules of the thyroid, and in one case the nodule was a branchial cyst.

CONCLUSION

Sonography can reveal the vagus nerve in healthy conditions and correctly reveal the vagal origin of some tumors in the parapharyngeal spaces.

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.

Airway obstruction in children due to plexiform neurofibroma of the larynx

Plexiform neurofibroma of the larynx is a rare disease. Three cases in children with airway obstruction are presented. After tumour reduction via a lateral pharyngotomy their tracheostomies could be closed. The surgical treatment of plexiform neurofibroma of the superior laryngeal nerve is discussed and conservative, subtotal resection is recommended.