• Korean Journal of Veterinary Research
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• v.54 no.1
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• pp.7-12
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• 2014

Peripheral nerve sheath tumors (PNSTs) are heterogeneous tumor groups of peripheral nerves that originate from either Schwann cells or modified Schwann cells, fibroblasts, or perineural cells. In this study, signalment and clinical data such as tumor location and size were evaluated for 15 cases of PNSTs collected from local animal hospitals. The mean age of dogs with malignant PNST was higher than that of dogs with benign PNST. Additionally, the male to female ratio in dogs with PNST was 1 : 4. In dogs with PNST, the primary sites of involvement were the hindlimb, forelimb, around the mammary glands, the neck, and the abdomen. Histiopathologic examination revealed that eight PNSTs were benign and seven were malignant. The tumor cells were composed of loosely to densely arranged interlacing bundles and wavy spindle cells arranged in short bundles, palisading, and whirling. High mitotic figures, local invasion, multifocal necrosis and atypical multinucleated giant cells were observed in malignant PNST cases. All PNSTs showed immunoreactivity for vimentin and S-100. However, only 93.3% and 73.3% were immunoreactive for NSE and GFAP, respectively. Overall, these results indicated that immunohistochemical markers such as vimentin, S-100 and NSE could help confirm the diagnosis of canine PNSTs.

• Journal of Korean Neurosurgical Society
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• v.61 no.5
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• pp.625-632
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• 2018

Objective : Because the anatomical structure of the brachial plexus is very complex, surgical treatment of tumors in this region is challenging. Therefore, a lot of clinical and surgical experience is required for successful treatment; however, many neurosurgeons have difficulty accumulating this experience owing to the rarity of brachial plexus tumors. The purpose of this report is to share our surgical experience with brachial plexus tumor with other neurosurgeons. Methods : The records of 18 consecutive patients with brachial plexus tumors who underwent surgical treatment between January 2010 and December 2017 in a single institution were retrospectively reviewed. The surgical approach was determined according to the tumor location and size, and intraoperative neurophysiological monitoring (IONM) was used in most of cases to prevent iatrogenic nerve injury during surgery. In addition, to evaluate the differences in tumor characteristics according to pathologic diagnosis, the tumors were divided twice into two groups, based on two separate classifications, and statistical analysis was performed. Results : The 18 brachial plexus tumors comprised 15 (83.3%) benign peripheral nerve sheath tumors including schwannoma and neurofibroma, one (5.6%) malignant peripheral nerve sheath tumor, one (5.6%) benign tumor of non-neural sheath origin (neurogenic cyst), and one (5.6%) metastatic tumor (papillary carcinoma). The authors analyzed relationship between tumor size/location and tumor characteristic parameters such as age, size, right-left, and pathology. There were no statistically significant differences except a tendency of bigger tumor size in young age. Conclusion : For a successful surgical outcome, an appropriate surgical approach is essential, and the appropriate surgical approach is determined by the location and size of the tumor. Furthermore, applying IONM may prevent postoperative complications and it is favorable option for brachial plexus tumors surgery.

• Investigative Magnetic Resonance Imaging
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• v.19 no.3
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• pp.153-161
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• 2015

Purpose: To identify the differential MRI findings between myxoid tumors and benign peripheral nerve sheath tumors (BPNSTs) in the musculoskeletal system. Materials and Methods: The study participants included a total of 35 consecutive patients who underwent MRI between September 2011 and December 2013. The patients were pathologically diagnosed with myxoid tumors (22 patients) or BPNSTs (13 patients). Evaluation was done by two radiologists, based on the following characteristics: size, margin, degree of signal intensity (SI) on T2-weighted images (T2WI), homogeneity of SI on T2WI, enhancement pattern, enhancement homogeneity, presence of cystic portion, internal fat component, presence of fat split sign, presence of target sign, presence of continuation with adjacent neurovascular bundle, and presence of surrounding halo. Results: Large size, high SI on T2WI, heterogeneous enhancement, and internal fat component were commonly observed in myxoid tumors, while homogenous enhancement, fat split sign, target sign were common in BPNSTs. The differences were statistically significant (P < 0.05). Other findings, such as margin, homogeneity of SI on T2WI, enhancement pattern (peripheral or solid), internal cystic portion, continuation with neurovascular bundle, and surrounding halo, did not show significant difference between myxoid tumors and BPNSTs (P > 0.05). Conclusion: In the differential diagnosis of myxoid tumors and BPNSTs involving the musculoskeletal system, several MRI findings such as degree of SI on T2WI, enhancement homogeneity, internal fat component, fat split sign, and target sign, may be helpful in establishing the diagnosis.

• Korean Journal of Head & Neck Oncology
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• v.31 no.2
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• pp.63-65
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• 2015

Nerve sheath myxoma is a benign tumor of the peripheral nerves that rarely occurs in the lip area. Among the few reported cases, no lesion has previously been reported on the lip in Korea. We report a case of nerve sheath myxoma occurring on the lip of a 34 year-old woman with a brief review of the literature.

• Korean Journal of Head & Neck Oncology
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• v.24 no.2
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• pp.174-178
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• 2008

Background and Objectives：Peripheral nerve sheath tumors(PNSTs) are uncommon neoplasm in the head and neck region. The treatment of PNSTs is surgical removal, but excision cause neurologic complications. This study was performed to evaluate the proper diagnosis and treatment of PNSTs with our experiences. Subjects and Method：During the period from October 1994 to July 2007, 58 patients were diagonised with PNSTs in head and neck region. We reviewed medical records and imaging study retrospectively. Result：95%(55/58) of the PNSTs in head and neck were benign；5%(3/58) were malignant peripheralnerve sheath tumors(MPNSTs). 63%(37/58) were neurilemoma, 20%(17/20) were neurofibroma, 2%(1/58) was perineuroma. 55 patients underwent surgery. 80%(45/55) of cases were treated with excision. Enucleation was performed in 7(14%) patients. All cases of benign neurogenic tumors showed no recurrence. Among 3 of MPNSTs 2 patients were Von Recklinghausen’s disease and expired with regional recurrence and lung metastasis. Conclusion：The benign PNSTs can be treated with enucleation if possible and observation can be another choice to minimize neurologic sequele.

• Korean Journal of Head & Neck Oncology
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• v.16 no.2
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• pp.224-227
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• 2000

Neurilemmomas are benign nerve sheath tumors arising from peripheral Schwann cells. The tumor composed of Schwann cells and collagen fibers, can occur in any region of the body where there is a nerve that has a Schwann sheath. The incidence of the tumor in the head and neck is about 30% with many of these occurring on the vagus nerve. Neurilemmoma is characterized by solitary occurrence, with sharp demarcation and encapsulation. Multiple genesis is very rare. This article presents a rare case of multiple neurilemmomas located bilaterally in the cervical region.

• Korean Journal of Head & Neck Oncology
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• v.18 no.2
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• pp.207-210
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• 2002

Schwannoma is a relatively rare benign tumor which may occur from nerve sheath of the peripheral, sympathetic and cranial nerves and so on except optic and olfactory nerves which have no nerve sheath themselves. Although it occur most frequently in the head and neck region especially in the acoustic nerve, the schwannoma originated from the motor nerves including hypoglossal nerve is very rare. Recently, we have experienced a case of schwannoma originated from hypoglossal nerve in a 47-year-old female. We report this case with literature review.

• Journal of Korean Neurosurgical Society
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• v.52 no.2
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• pp.138-143
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• 2012

Objective : This is a retrospective review of 22 surgically treated benign and malignant tumors of brachial plexus region to describe clinical presentation, the characteristics of brachial plexus tumor and clinical outcomes with a literature review. Methods : Twenty-one patients with consecutive 22 surgeries for primary brachial plexus tumors were enrolled between February 2002 and November 2011 were included in this study. The medical records of all patients were reviewed. Results : Eleven male and 10 female patients were enrolled. Mean age was 39 years. Three patients had brachial plexus tumor associated with neurofibromatosis (13.6%). Presenting signs and symptoms included parenthesis and numbness (54.5%), radiating pain (22.7%), direct tenderness and pain (27.2%), palpable mass (77.3%). Twelve patients presented preoperative sensory deficit (54.5%) and 9 patients presented preoperative motor deficit (40.9%). Twenty tumors (90.9%) were benign and 2 tumors (9.1%) were malignant. Benign tumors included 15 schwannomas (68.2%), 4 neurofibromas (18.2%) and 1 granular cell tumor (4.5%). There were 1 malignant peripheral nerve sheath tumor (MPNST) and 1 malignant granular cell tumor. Gross total resection was achieved in 16 patients (72.7%), including all schwannomas, 1 neurofibroma. Subtotal resection was performed in 6 tumors (27.3%), including 3 neurofibromatosis associated with brachial plexus neurofibromas, 1 MPNST and 2 granular cell tumor in one patient. Conclusion : Resection of tumor is the choice of tumor in the most of benign and malignant brachial plexus tumors. Postoperative outcomes are related to grade of resection at surgery and pathological features of tumor.

• Korean Journal of Head & Neck Oncology
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• v.25 no.2
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• pp.171-173
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• 2009

Neurilemmoma is a relatively rare benign tumor which may be derived from nerve sheath of the peripheral, sympathetic and cranial nerve except the optic nerve and olfactory nerve. And it is a characteristically solitary and well-encapsulated mass. About 25% of neurilemmoma occurs in the head and neck region and the acoustic nerve is most frequently involved, but neurilemmoma of the larynx is rare. Recently, we experienced a case of neurilemmoma occurred in the right aryepiglottic fold of the larynx. The tumor was successfully removed by transoral approach under direct laryngoscope. So we report this case with literature review.

• Investigative Magnetic Resonance Imaging
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• v.23 no.4
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• pp.385-389
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• 2019

Schwannoma or neurilemmoma is a benign peripheral nerve sheath tumor that arises from Schwann cells. Approximately 25-45% of all schwannomas occur in the head and neck regions, and the intraoral presentation of these is only 1%. We report a rare case of a patient presenting tongue base schwannoma with characteristic imaging features on computed tomography and magnetic resonance imaging.