• The Korean Journal of Cytopathology
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• v.19 no.1
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• pp.41-46
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• 2008

In an attempt to better define the cytologic characteristics of schwannomas, we have reviewed aspirates and corresponding histologic sections from 23 schwannomas. Of this number, the original cytologic diagnoses were: schwannoma in 14 cases (61%), benign soft tissue tumor in 2 cases (9%), and insufficient specimen in 7 cases (30%). The cytologic findings common to all cases of schwannoma included fragments of tightly cohesive fascicles with variable cellularity and corresponding Antoni type A area. The Antoni type B area, consisting of scattered spindle cells and some histiocytes and lymphocytes against a myxoid background, was seen in 14 cases. Fibrillary stroma was seen in 12 cases. The tumor cells had spindle- or ovalshaped nuclei, with pointed ends and indistinct cell borders. Nuclear palisading was seen in 10 cases, and distinctive Verocay bodies were seen in 5 cases. In ancient schwannomas, there were no Verocay bodies. Most schwannomas have distinct cytomorphologic features that allow correct diagnosis. The major problem with fine needle aspiration cytology of these tumors is the high frequency of poor cellularity, particularly in lesions with cystic degeneration. Of 7 cases with insufficient specimen, 4 showed marked cystic changes and 1 showed marked hyaline changes on histologic sections. In conclusion, we believe that if cytopathologist reminds the situation such as cystic degeneration or hyaline degeneration, the correct diagnosis of the schwannoma will be easily made.

• Journal of Chest Surgery
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• v.11 no.3
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• pp.239-245
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• 1978

Recently, we experienced a case of rare neurilemmoma originated from intercostal nerve [9th] in the right chest wall in a 25 year old male officer. The tumor was incidentally found in the routine chest X ray, where the round well circumscribed mass tumor the ninth rib with notching and sclerotic margin, suggesting slowly growing benign benign of chest wall was revealed and the tumor mass was easily extirpated in the exploratory thoracotomy, with uneventful recovery. Grossly, the tumor was firm, partly soft and well circumscribed, measuring 4.5X3.0X 3.0 cm with yellowish smooth outer surface, attached with intercostal nerve trunk. Cut surface exhibits partly grayish white and largely hemorrhagic areas. Microscopically, the characteristic palisading arrangement of schwann cells and Verocay bodies are seen but dominant features are cystic degeneration and hemorrhage with organization and fibrosis. The sheath of intercostal nerve and capsule of neurilemmoma were con joined. There is no evidence of malignancy. The tumor was confirmed as neurilemmoma of intercostal nerve, Antony type B.

• The Korean Journal of Cytopathology
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• v.1 no.2
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• pp.158-163
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• 1990

Ancient (degenerated) schwannomas are benign tumors that display pronounced degenerative changes including cyst formation, calcification, hemorrhage, and hyalinization. The tumors are usually infiltrated by large numbers of inflammatory cells such as neutrophils, lymphocytes, siderophages, and histiocytes. They are located in deep locations such as the retroperitoneum and must be differentiated from malignant soft tissue tumors because spindle cells with nuclear atypia may be present. In the fine needle aspiration biopsy. The cytologic findings of two cases of ancient schwannoma occurring in posterior mediastinum and retroperitoneum, respectively, are described. Computerized tomographic findings of both cases showed changes of cystic degeneration or necrosis. A case occurred in retroperitoneum revealed features of destruction of vertebral body to suggest a malignant soft tussue tumor radiologically. The cytologic findings of aspiration biopsy of both tumors revealed that the tumor cells were spindle in shape with elongated nuclei. Some of tumor cells were arranged in a palisading fashion. Cell structures that resemble the Verocay bodies were observed. Some of the tumor cells showed pleomorphic bizarre nuclei, but no mitotic activity or chromatin clumping was seen. Inflammatory cells, siderophages and histiocytes were scattered in fibrillar material. These cytologic findings are important in the diagnosis of ancient schwannoma and in the differentiation of this tumor from the malignant spindle cell tumor.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.31 no.1
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• pp.89-93
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• 2005

Intraosseous neurilemmoma(Schwannoma) is an extremely rare benign neoplasm. The site most commonly involved is the mandible. This occurrence is understandable because of the length of the inferior alveolar canal through the mandible. No other bone contains a canal that transmits a neurovascular bundle of such size and length. We report on a peripheral and central neurilemmoma along pathway of inferior alveolar nerve of the lower lip and mandible in a 28-year old man. A panoramic radiograph of the mandible showed a well-defined bilocular lesion with a thin uniform sclerotic margin located in the ramus and body of the mandible. The CT scan confirmed a well-defined lesion with thinning of the cortex of the body of the left side of the mandible. Histologically, the lesion was a cellular neoplasm with distinct palisading and numerous Verocay bodies. Complete excision was achieved by removing the tumor with the inferior alveolar nerve.

• Tuberculosis and Respiratory Diseases
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• v.46 no.4
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• pp.580-585
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• 1999

Neurilemmoma is a benign nerve sheath tumor derived from Schwann cells and occurs in the head, neck, flexor regions of the extremities, posterior mediastinum but extremely rare in the chest wall. They occur at all ages but are most common in persons between the ages of 20 and 50 years and develop spontaneously or possible as a result of trauma or irritation. The diagnosis of a neurilemmoma is confirmed histologically by the findings of Verocay bodies, Antoni A and B tissue patterns and the presence of S-100 protein. We experienced a case of chest wall neurilemmoma which was treated by local excision and report it with a brief review of the literature.

• Tuberculosis and Respiratory Diseases
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• v.49 no.2
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• pp.225-230
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• 2000

Neurilemmoma is rare benign tumor originating from the Schwann cell of the nerve sheath. Intrabronchial neurilemmoma are extremely rare and only few cases have been reported previously in Korea. Neurilemmoma at all ages but are most common in persons between the ages of 20 and 50 years. It affects the head, neck, flexor regions of the extremities. Neurilemmoma was confirmed histologically because of the presence of Verocay bodies, Antoni A or B tissue pattern and of S-100 protein. We report two cases of intrabronchial neurilemmoma with chronic coughing and nonspecific radiologic findings.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.49 no.4
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• pp.233-238
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• 2023

Schwannomas exhibit histopathological variation that leads to diagnostic dilemmas, although less frequent in the oral cavity. We describe a case with unique histopathology and no relevant clinical history that adds to the breadth of literature on the diversity presented by Schwannoma. A 60-year-old female patient presented with a small dome-shaped, asymptomatic swelling on the alveolar ridge 6 years in duration. Histopathologically, it showed rich cellular pathology with a unique arrangement of tumor cells forming irregular rosettes. Each rosette presented with a central core of fibrin-collagenous material and the tumor cells were arranged on the periphery, exhibiting epithelioid change with evidence of mild cellular and nuclear pleomorphism. On immunohistochemical evaluation, the cells were strongly and diffusely positive for S-100 and negative for Ki-67. A diagnosis of benign Schwannoma with a rosette-like arrangement with epithelioid change was made. The case report emphasizes the risk of misdiagnosis and the importance of awareness regarding rare histopathological variants of Schwannoma.

• The Korean Journal of Cytopathology
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• v.10 no.1
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• pp.55-60
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• 1999

Schwannoma is a benign encapsulated nerve sheath tumor and is histologically characterized by a mixture of Antoni type A and B tissue. A preoperative diagnosis of schwannoma by fine needle aspiration cytology or by any other means is important a preserve clinically important nerves. Therefore, it is necessary to make a specific cytological diagnosis of nerve sheath tumor. However, there are a few reports regarding cytological features of schwannoma in Korea. We experienced seven cases of solitary schwannoma and here we report their characteristic cytological features with a review of literatures. The characteristic features of schwannoma on cytology were the presence of both Antonl type A and B tissue. The cytologic findings common to all cases of schwannoma generally corresponded to the histologic findings of Antoni type A tissue, consisting of fragments of tightly cohesive fascicles with variable cellularity. Dense fibrillary substances were found, along with palisading nuclei and Verocay bodies. Individual tumor cells consisted of cohesive cells haying spindle or oval nuclei, with pointed ends and Indistinct cell borders. Variation in nuclear size and shape was also present. The Antoni type B consisted of scattered wavy or short spindle cells and some histiocytes and lymphocytes in the abundant myxoid background with formation of microcysts. Immunohistochemistry for S-100 protein revealed a uniformly strong positive reaction and was helpful to make more accurate diagnosis of schwannoma.

• Tuberculosis and Respiratory Diseases
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• v.65 no.4
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• pp.318-322
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• 2008

Neurilemmomas are benign nerve sheath tumors derived from Schwann cells that rarely occur in the chest wall. Neurilemmomas of the chest wall are usually solitary lesions that bulge toward the pleural cavity. Neurilemmomas are confirmed histologically based on the presence of Verocay bodies, Antoni A and Antoni B tissue patterns and S-100 protein. Bilateral neurilemmomas in the chest wall are extremely rare, as are those that grow in the subcutaneous tissue but not the pleural area. We report here a case of bilateral chest wall neurilemmomas in which the tumors bulged out to the skin and were palpable.