• The Journal of the Korean bone and joint tumor society
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• v.2 no.1
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• pp.88-93
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• 1996

Neurilemmomas are the most common benign tumor of the peripheral nerve trunks, and arises from the cells in the sheath of Schwann. Neurilemmomas are well encapsulated and may be separated easily from surrounding tissue and lie completely within a larger nerve trunk, with bundles of neurofibrils spread out over the surface of the tumor. A careful dissection and retraction of the nerve bundles will allow the tumor to be enucleated from the parent nerve without any significant interference with the function of the nerve. Resection of the involved nerve is seldom necessary and should be avoided if at all possible. Our aim in microscopic excision of neurilemmoma of extremities is to reduce any disturbance of the intact neurofibrils of the parent nerve. Thirteen cases of neurilimmomas were treated by microscopic excision at the Department of Orthopaedic Surgery, Korea University Hospital between January 1990 and March 1995. The results was as follows ; 1. The average age at surgical intervention was 40.1 years. Cases in fourth and fifth decades predominated. 2. In their anatomical distribution, 8 cases were in the upper extremity and 5 cases in the lower extremity. 11 cases were on the flexor surface. 3. On the operative field, all the tumors were well encapsulated, however 1 case of 13 was adherent to the periosteum of fibula. 4. In all cases, the tumor were enucleated from the parent nerve without any injury to nerve under high-power magnification, preserving individual fascicles, and sensory and motor function.

• Archives of Craniofacial Surgery
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• v.20 no.6
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• pp.388-391
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• 2019

Schwannoma is a slow-growing, well-demarcated, benign soft tissue tumor of the peripheral nerve sheath. It commonly develops in the head and neck region, usually in the parapharyngeal space. In this case, a 42-year-old woman visited the outpatient department to manage a painless mass on her left cheek. She had no history of concern and no neurological symptoms were observed. In the enhanced computed tomography scan, a 2.8×2.8×1.8 cm, heterogeneously enhanced tumor was detected in the left masseter muscle. A tumor resection under general anesthesia was planned. For the resection, a facelift incision was chosen; branches of the facial nerve were identified and retrogradely dissected. A well-marginated, yellowish, solid mass was found in the left masseter muscle. The mass was excised and given a histopathological diagnosis of schwannoma. A definite diagnosis of schwannoma, originating in the masseter muscle, is difficult to arrive at with radiographic findings alone; it is often misdiagnosed as intramuscular hemangioma. Histopathological examinations, including fine-needle aspiration or histological biopsy after surgery, are necessary. Using a facelift incision with retrograde facial nerve dissection, tumor resection in an intramasseteric lesion can be performed efficiently, without nerve damage, or leaving conspicuous scars on the face.

• Archives of Plastic Surgery
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• v.38 no.4
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• pp.498-500
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• 2011

Purpose: Neurilemoma is benign tumor of the nerve sheath which arises from Schwann cells. It is usually formed along the path of a peripheral nerve but is rarely separate from normal nerve fascicles. We experienced a patient with an isolated neurilemoma localized in the palmaris longus tendon with no connection to the major nerve trunk, which was in an unusual location and has never been reported. We report our case with the review of the literature. Methods: A 23-year-old female visited our clinic with mild pain on the mass at the flexor area of the right wrist which had been present for about one year. The physical examination revealed a $1{\times}1cm$ sized subcutaneous mass at the flexor area of the right wrist. Sonography and computed tomography showed an ovoid, superficial solid mass on the palmaris longus tendon. Upon surgical excision, a $1{\times}0.5cm$ sized mass attached to the palmaris longus tendon was found. The tumor had no connection with the median nerve and was detached easily from the palmaris longus tendon. Results: Histological examination demonstrated the mass to be a neurilemoma, which consists of spindle shaped cells with oval elongated nuclei arranged fascicles. No sensory dysfunction or evidence of recurrence was found during the 12 months of postoperative follow-up. Conclusion: We experienced a rare case of neurilemoma attached to the palmaris longus tendon with no connection to the major nerve trunk. We wish to emphasize its unusual location through our case and hope to expand our spectrum in exploring the upper extremity mass.

• Korean Journal of Veterinary Service
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• v.41 no.1
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• pp.57-61
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• 2018

Canine peripheral nerve sheath tumors (PNSTs) are spindle cell tumors that arise from Schwann cells, perineural cells, fibroblasts or all of them. Based on the morphology and biologic behavior, PNSTs are divided into benign PNST (BPNST) and malignant PNST (MPNST) forms. The aim of this study is to diagnose the two cases of neoplastic tissue samples with features of PNSTs by the histopathology and immunohistochemistry. The study was performed using two specimens from small animal clinic. The first case, A was a mass, 3~4 cm in diameter, extruded from vaginal mucosa of 10-year-old spayed female mixed-breed dog. And the second case, B was a subcutaneous mass, 1.5 cm in diameter, which is originated from right hind leg of 9-year-old castrated male mixed-breed dog. Two cases were stained with hematoxylin and eosin (H&E) for histopathological examination. And also immunohistochemistry (IHC) was performed by the avidin-biotin peroxidase complex (ABC) method with antibodies specific for the following proteins: S-100 protein, smooth muscle actin (SMA) and epidermal growth factor receptor (EGFR). In results, Antoni B schwannoma pattern characterized by pleomorphic, round and fusiform polygonal cells was seen in A. In B, Antoni A pattern, densely packed spindle cells arranged in interlacing bundles was seen in addition to Antoni B pattern. In IHC, cytoplasms of neoplastic cells were diffusely labeled for S-100 expression in A and B. For SMA, both A and B show negative expression. And for EGFR, A shows negative expression but B shows partially positive expression in areas of Antoni B schwannoma pattern. The histopathologic features of two cases coupled with the S-100 immunoreactivity led to a diagnosis of PNST. For SMA, both A and B show negative expression. The diagnosis of A will be a BPNST with the negative result and B will be a MPNST with the positive result for EGFR.

• The Journal of the Korean bone and joint tumor society
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• v.5 no.1
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• pp.44-50
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• 1999

Neurilemmoma is a benign encapsulated nerve sheath tumor originated from peripheral nerve. Previously its preoperative diagnosis had mainly depended on the history, physical examination, electrodiagnostic test, ultrasonography, bone scan. But only with these diagnostic modalities, exact preoperative diagnosis was nearly impossible. Therefore operation was performed under the impression of lipoma or just simple soft tissue tumor. Recently, the advent of magnetic resonance imaging(MRI) has made it easier to diagnose neurilemoma before surgery. MRI also helps to determine the extent of lesion and operative procedures. We performed marginal excision in 24 cases, evaluated those cases with respect to the sex, age, location, chief complaint, duration of illness, preoperative diagnosis, involved nerve, imaging studies, size of mass, complication, duration of follow-up and report with review of the literature.

• Korean Journal of Head & Neck Oncology
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• v.33 no.2
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• pp.95-99
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• 2017

Schwannoma, also known as a neurilemmomas or neurinomas, is benign peripheral nerve sheath tumors arising from the Schwann cells. About 25~45 % of all schwannomas are found in the head and neck region, and the majority are found in the parapharyngeal space. Schwannoma of the larynx is very rare with an incidence of 0.1~1.5% in all benign laryngeal tumors. Recently, we experienced a case of a pedunculated schwannoma arising from the left aryepiglottic fold in a 80-year-old patient. The tumor was completely excised under direct laryngoscopy with the use of a $CO_2$ laser and subsequently confirmed as schwannoma. So, we report this case with a review of the literatures.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1981.05a
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• pp.14.1-14
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• 1981

Neurofibroma are slow growing benign tumors arising from the neurilemal sheath (Schwann cells) and fibroblasts of the peripheral nerve. This benign tumor may occur as a solitary lesion or as a part of the syndrome of neurofibromatosis. The neurofibroma of oral tissues is rare in otolaryngologic field and usually presents as a firm, elevated, nonpainful lesion that shows the usual histologic findings of a neurofibroma or neurilemmoma. Recently, we have experienced a neurofibroma arising from the tongue in a 54 year old female and removed successfully under local anesthesia. No evidence of recurrence has been observed up to date.

• Archives of Plastic Surgery
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• v.37 no.4
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• pp.452-456
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• 2010

Purpose: The schwannoma is a benign peripheral nerve tumor arising from the Schwann cell of the nerve sheath. Only 2-8% of schwannomas arise in the hand and wrist. Misdiagnosis is frequent such as ganglion and neurofibroma. This article documents and clarifies the clinical features of schwannomas arising in the hand and wrist, and emphasizes importance of differential diagnosis and meticulous surgical extirpation under magnification. Methods: The author reviewed clinical features of 15 patients with pathologic final diagnosis of schwannoma developed in hand and wrist during the last 12 years from 1998 through 2009. The review included the sex, age of onset, duration, preoperative diagnosis, location, involved nerve, preoperative symptoms and. Postoperative sequelae after surgical extirpation of the lesion with magnification, or without magnification of the surgical fields. Results: The chief complaints were slow growing firm mass in all patients, and followed by pain in 40%, and paresthesia in 40% respectively. The lesions were developed solitarily in 14 patients (93%). The postoperative pathologic diagnosis and preoperative diagnosis were coincided with only in 6 patients (40%). Other preoperative diagnosis were soft tissue tumor in 4 patient (26.6%), and ganglion in 3 patients (20%), and neurofibroma in 2 patients (13%). In all patients who were undergone surgical excision under the fields of magnification, all symptoms were subsided without any sequelae. Meanwhile muscle weakness, paresthesia, hypoesthesia and /or accidental nerve resection developed after surgical excision with naked eye. Conclusion: Schwannoma in hand most commonly appears as a slow growing solitary mass with pain or paresthesia. The chance of preoperative misdiagnosis was 60% in this series. To provide good prognosis and less sequelae, careful and elaborate diagnostic efforts and meticulous surgical excision under the magnification are necessary in management of schwannoma.

• Archives of Plastic Surgery
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• v.38 no.6
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• pp.890-893
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• 2011

Purpose: Schwannoma is a slow-growing, encapsulated benign peripheral nerve tumor that originates from the Schwann cell of the nerve sheath. Schwannoma most frequently involves the major nerve. Schwannoma of the foot is rare. This is a report of our experience with a small, deep-seated, and non-palpable schwannoma occurring in the foot. Methods: A 42-year-old woman presented with the plantar pain of the right foot during 2 years. Physical examination did not identified a palpable mass. She made a clinical diagnosis of plantar fasciitis and was conservatively treated 2 years ago. Since her plantar foot pain was aggravated, she was recently visited again. For the evaluation of her plantar foot pain, sonographic examination of the whole right foot was performed, and it revealed a small hypoechoic hetergenous, deep-seated mass beneath the plantar aponeurosis. At operation, a $0.7{\times}0.6{\times}0.4$ cm sized, ovoid, yellowish grey mass was removed. Results: Histology was confirmed that the mass was a benign schwannoma. There were no postoperative complications. Conclusion: Unsusual case of a schwannoma with the plantar foot pain during 2 years is presented. It should be recognized a small, deep-seated, non-palpable

• Korean Journal of Head & Neck Oncology
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• v.26 no.1
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• pp.37-40
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• 2010

Ectopic hamartomatous thymoma is a rare benign tumor of the lower neck occurring in the male adult predominantly. The origin of this tumor has been debated, but it is now believed to arise from remnants of the cervical sinus of His from early development. They are composed of epithelial, adipocytic, and spindle cells in variable amounts. Recognition of ectopic harmatomatous thymoma is important and needs to be differentiated from high-grade sarcomas such as synovial sarcoma or glandular malignant peripheral nerve sheath tumor. We here report on a case of ectopic hamartomatous thymoma arising in the left lateral neck of 33-year-old male patient.