|Year : 2020 | Volume
| Issue : 1 | Page : 42-45
Giant cervico-pectoral schwannoma
Suresh C Sharma, Kuldeep Thakur, Prem Sagar, Dhananjay Kumar
Department of Otolaryngology & Head and Neck Surgery, AIIMS, New Delhi, India
|Date of Submission||21-Mar-2020|
|Date of Acceptance||28-Apr-2020|
|Date of Web Publication||18-Jun-2020|
Department of Otolaryngology, Head and Neck Surgery, ENT Office 4057, 4th Floor, Academic Block, AIIMS, New Delhi - 110 029
Source of Support: None, Conflict of Interest: None
Benign tumors of brachial plexus (BP) are relatively rare. However, these tumors pose a surgical challenge due to their origin in an anatomically complex region containing neurovascular tissue nexus. We describe a case of giant BP schwannoma involving the right neck and supraclavicular fossa extending to the right pectoral region without any associated neurological deficit.
Keywords: Brachial plexus, nerve sheath tumor, schwannoma
|How to cite this article:|
Sharma SC, Thakur K, Sagar P, Kumar D. Giant cervico-pectoral schwannoma. J Head Neck Physicians Surg 2020;8:42-5
| Introduction|| |
Schwannoma is a benign, well-encapsulated, slow-growing neoplasm arising from Schwann cells present in the nerve sheath of cranial, spinal, autonomic, and peripheral nerves. Approximately 25%–48% of all extracranial schwannoma are found in the head-and-neck region, with tumors of brachial plexus (BP) origin being even rarer.
The first case of BP schwannoma was described by Courvoisier in 1886 arising from C5 spinal nerve root and unfortunately, tumor excision was associated with paralysis of biceps and deltoid muscles. In the current world literature, most of the available data of BP schwannoma are from small case series except two large retrospective studies from tertiary referral centers., The operating experience on these tumors in terms of functional results is also limited and presents a great challenge to the surgeons. In view of the complex anatomy of BP, associated anatomical variations, and critical role in upper limb functioning, management of these tumors requires multidisciplinary care and appropriate surgical approaches.
Rarely, these tumors may be a manifestation of neurofibromatosis type 2 (NF2) characterized by the presence of tumors of the central and peripheral nervous system, sometimes accompanied by cutaneous lesions.
We present a case of giant cervico-pectoral schwannoma associated with plexiform schwannoma, unilateral vestibular schwannoma, and multiple schwannomas involving conus medullaris, cauda equina, and filum terminale.
| Case Report|| |
A 38-year-old male patient presented with the chief complaint of a diffuse swelling in the right lower neck and upper chest for 6–7 years, which was insidious in onset and progressively increased in size, not associated with other symptoms. He also had a history of impaired hearing from the left ear for 6–7 years, which was insidious in onset, progressively deteriorated, and not associated with tinnitus and vertigo. Further, otoscopic, nasal, pharyngeal, and laryngeal examination was normal. Findings on tunic fork tests were suggestive of sensorineural hearing loss in the left ear, which was subsequently confirmed on audiological analysis. On neck examination, a diffuse, ill-defined, nontender, soft mass was palpable involving the right lower neck and supraclavicular region extending deep into the clavicle and reaching up to the right deltopectoral groove [Figure 1]. Another small soft, nontender, mobile, subcutaneous nodule of 1.5 cm × 1 cm in size was present near the insertion of the clavicular head of the right sternocleidomastoid muscle. There were no signs suggestive of thoracic inlet obstruction. Rest of the systemic, ophthalmological, and neurological examination was within normal limits. On gadolinium-enhanced magnetic resonance imaging (MRI), there was a well-defined tubular-shaped mass involving the right supraclavicular region extending deep into the clavicle into the right pectoral region, with T2-weighted images showing peripherally high signal intensity and relatively low signal intensity at the center of the lesion [Figure 2] and [Figure 3]. T2-weighted (axial scan) image of the inner ear and cerebellopontine angle showed typical ice cream cone appearance of left vestibular schwannoma [Figure 4]. Preoperative fine-needle aspiration cytological analysis was suggestive of schwannoma. Screening for neurofibromatosis could not be done due to financial constraints. The patient underwent excision by anterior combined supra- and infraclavicular approach under general anesthesia, and a 20 cm × 8 cm smooth, well-defined mass with attached satellite nodules was excised and sent for histopathological examination [Figure 5]. Histomorphological features were suggestive of schwannoma, and histomorphological features of a separate skin nodule were consistent with plexiform schwannoma [Figure 6]. In the immediate postoperative period, the patient developed weakness of the right deltoid and triceps muscles (power 2/5), suggestive of origin from the posterior cord of BP. On follow-up, muscle weakness improved (power 4/5), and electromyography performed 3 months postsurgery showed features of recovery. Currently, the patient is in neurosurgery follow-up for the management of left vestibular schwannoma.
|Figure 1: Diffuse ill-defined mass involving the posterior triangle of the neck, extending to the right pectoral region up to the right deltopectoral groove beneath the clavicle|
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|Figure 2: T2-weighted (coronal scan) images showing peripheral high signal intensity with relatively low signal intensity in central areas|
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|Figure 3: T2-weighted (axial scan) images showing a well-defined mass with peripheral high signal intensity and relatively low signal intensity in central areas, tumor seated deep into the clavicle bone|
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|Figure 4: T2-weighted (axial scan) images showing typical ice cream cone appearance of left vestibular schwannoma (due to extension, i.e., the cone, of the tumor into the intracanulicular part with ice cream scoop appearance on the top at the cerebellopontine angle)|
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|Figure 5: A 20 cm × 8 cm, smooth, well-defined, bean-shaped mass with attached satellite nodules|
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|Figure 6: A spindle cell tumor with hypercellular areas (Antoni A type) and nuclei arranged in alternating parallel rows forming palisades (Verocay bodies) (×40)|
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| Discussion|| |
Schwannomas arising from BP are relatively rare and constitute <5% of all neurogenic upper limb tumors. Majority of patients present in the third and fourth decades with a palpable lump, whereas pain and paresthesia are present in few patients. Tinel sign, an electric shock-like sensation in the territory of entrapped nerve if present, should be considered the diagnostic of nerve tumor. In majority of cases, despite the large size of tumor, no neurological deficits are demonstrated, thus creating a surgical challenge in terms of preservations of neurological functions postoperatively. In rare instances, these lesions may present with acute neurovascular symptoms secondary to infarction or hemorrhage within the lesion, resulting in tumor swelling and rapid increase in size, thus accounting for the acute-onset symptoms., Because of the large size of the lesion in the present case, it was more susceptible to intratumoral necrosis or hemorrhage, which could have resulted in acute neurovascular compromise of the upper limb.
Most BP tumors are benign with malignant tumors, constituting <10% of all tumors of BP origin. Malignant BP tumors include neurogenic sarcomas and neurofibrosarcoma and are aggressive and fast growing with rapid-onset neurological deficits.
Preoperative fine-needle aspiration cytology or core needle biopsy is usually discouraged because of lack of accuracy and may cause iatrogenic damage to nerve fibers. If biopsy is attempted before surgery, dissection during surgery may become difficult due to fibrosis and can cause injury to neural fascicles. Preoperative electrophysiological studies are not routinely recommended because they do not contribute in the diagnosis or in the planning of surgical excision although they help in documenting the degree of neural involvement.
MRI scan is the imaging modality of choice to diagnose BP tumors.
T1-weighted images show homogeneous and isointense signal to muscle, whereas T2-weighted images show peripherally high signal intensity and centrally relatively low signal intensity. On gadolinium-enhanced T1 images, centrally high intensity by focal enhancement and peripherally low intensity are seen. It clearly delineates the margins of benign BP tumor from the surrounding tissue and important vital structures such as subclavian and axillary arteries and other neural elements of the BP although differentiation between benign and malignant BP tumors is difficult. However, the associated bony destruction or erosion and infiltrative irregular margins are suggestive of malignancy. In contrast to neurofibroma, peripheral orientation of tumor in relation to the neural elements helps in diagnosing schwannoma. MR neurography, a newer modality, has potential to demonstrate the entire course of the associated nerve in relation to tumor.
Pain, progressive neurological deficit, increasing size, local pressure symptoms, and disfigurement associated with tumors are considered indications for surgery.
Intracapsular enucleation with preservation of nerve fibers is the treatment of choice and preferred to tumor resection with end-to-end anastomosis., Majority of patients following surgical resection do not show aggravation of pain or motor function, but 10%–17% of patients may have new-onset neurological deficit with variable severity.
Anterior supra- or infraclavicular approach is standard for the excision of BP schwannoma. In the present case, in view of the larger size of the tumor, we used combined anterior supra- and infraclavicular approach without splitting the clavicle.
Macroscopically, these tumors are well circumscribed with cystic degeneration and may contain hemorrhagic foci within the tumor. On microscopic examination, lesions display a biphasic pattern with Antoni A (consists of compact collection of spindle-shaped cells arranged in sheets and palisades with pathognomic Verocay bodies) and Antoni B (consists of loose myxoid matrix and collagen fibrils often with cystic spaces intermixed within the tissue and few scattered spindle cells). On immunohistochemistry, these tumors show intense S100 antigen positivity. In addition, Leu-7, epithelial membrane antigen, neurofilament protein, Vimentin, and collagen are also valuable markers in the diagnosis of schwannoma.
Presence of unilateral vestibular schwannoma in combination with schwannoma, glioma, meningioma, or posterior subcapsular opacities raises the suspicion of NF2 and should be screened. In patients with NF2, biannual screening in childhood and then yearly thereafter is strongly recommended with special emphasis on neurologic and ophthalmologic examination.
| Conclusion|| |
BP schwannoma is a rare entity and usually presents as a asymptomatic, slow-growing tumor. Despite being asymptomatic and benign in nature, giant BP schwannoma requires aggressive treatment as underestimation may cause damage to the adjacent neurovascular structures and upper limb neurovascular compromise secondary to local mass effect or vascular events.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
This material has never been published and is not currently under evaluation in any other peer reviewed publication.
The permission was taken from Institutional Ethics Committee prior to starting the project. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from the participant in the study.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]