Intraosseous neurilemmoma of the proximal ulna

Imaging Features of Intraosseous Schwannoma: A Case Series and Review of the Literature

To characterize the imaging features of patients with pathologically confirmed intraosseous schwannoma (IOS), institutional pathology and imaging databases were searched for IOS cases over a period of 17 years. A musculoskeletal radiologist evaluated all imaging studies. Additionally, a literature search was performed to identify IOS cases that had imaging findings of at least two modalities. Six patients (one female, five males, mean age of 50 ± 14 years) with IOS were identified, with all lesions localized to the lumbosacral region. Radiographic imaging was available in four patients, while all patients underwent CT and MR imaging. Radiographs depicted lytic lesions, and CT depicted heterogeneous expansile lesions with centrally hypodense areas and peripheral sclerosis. All cases involved extra-osseous extension, producing a mass effect on adjacent soft tissues and nerve roots. On MRI, the neoplasms displayed iso- to- slightly- low signal intensity on T1-weighted images and hyperintense signal intensity on T2-weighted images with heterogeneous enhancement. The literature review resulted in 102 IOS cases, which to the best of our knowledge, is the largest review on IOS, and the imaging findings of the previously published cases were the same as our cases. IOSs are rare benign neoplasms that should be considered in the differential diagnosis of well-defined expansile lytic lesions with sclerotic borders. This is particularly important in middle-aged adults with mandibular, sacral, or vertebral body mass.

Intraosseous schwannoma of distal femur: A case report

Introduction and importance

Intraosseous schwannoma is a rare benign tumor, which mostly occurred in head and neck region. In this report we aimed to describe a unique case of intraosseous schwannoma in the distal femur without any other clinical finding aside from pain and tenderness.

Case presentation

19-year-old female presented with persistent pain on her left thigh for 4 years. Aside from tenderness on her left thigh, her physical examination was unremarkable. Plain radiographic of left femur showed a small geographic osteolytic cortical lesion with sclerotic rim in the distal region. Further evaluation with MRI showed eccentric lytic lesion with an isointense signal on T1-weighted images and a hyperintense signals on T2-weighted images. Patient then temporarily diagnosed with osteoblastoma. Because there were no signs of malignancy, the patient underwent a curettage of the mass followed by synthetic bone graft application. Histopathological findings were consistent for schwannoma. Further immunohistochemical examination showed positive S100 staining, confirming the final diagnosis of intraosseous schwannoma. There were no signs of early complication on 3 months post-operation. The patient was further scheduled for follow up on 6 months and then routinely every year post-operation to evaluate any signs of complication or recurrence.

Clinical discussion

It is difficult to make an accurate initial diagnosis of intraosseous schwannomas. Because the clinical presentation was most likely not specific as such in this case and there many other tumors of the bone with similar radiographic finding which are more common. Curettage of the mass followed by synthetic bone graft application was performed as there were no sign of malignancy making more invasive option deemed to cause more harm than good to the patient.

Conclusion

The possibility of intraosseous schwannoma should have been taken under consideration in the differential diagnosis of osteolytic lesion with pain in long bone.

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Clinical presentation of intraosseous schwannoma can be non-specific

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Radiological findings of intraosseous schwannoma can mimic more common condition of the bone such as osteoblastoma, non-ossifying fibroma, and simple bone cyst

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Histopathological and immunohistochemical analysis is important to established the final diagnosis

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Curettage of the mass followed by synthetic bone graft application are adequate for intraosseous schwannoma as it is a benign condition with almost negligible potential to become malignant.

Intraosseous schwannoma of the proximal humerus with pathologic fracture

BACKGROUND

Intraosseous schwannomas are extremely rare in the humerus, and less than five cases have been reported previously in the literature. This is the first report of its origin in the proximal humerus with pathologic fracture. We herein present this case to discuss the reason for its rarity and share our experience of management.

CASE PRESENTATION

A 55-year-old female patient presented with pain in the right shoulder, which was caused by tripping and falling over a board. Radiographs, computed tomography (CT) and magnetic resonance imaging (MRI) showed considerable tumor in proximal humerus, which connected with a fracture. For this suspected tumor, we performed two operations. Pathological examination demonstrated typical picture of a schwannoma, showing whorls and interlacing fascicles of schwannoma spindle cells. Immunohistochemistry, the tumor cells were diffusely positive for S-100 protein, SOX-10 and CD68, while they were completely negative for desmin, DOG-1, AE1/AE3 and P63. The Ki-67 index was about 10%. No mitoses or features of malignancy were identified. The final diagnosis of intraosseous schwannoma was made. The treatment for intraosseous schwannoma with pathologic fracture includes excisional biopsy, curettage, bone allograft, and fracture fixation. The patient recovered well. After the surgery, the patient gradually regained mobility and the pain subsided. There was no recurrence after 6 months of follow-up by X-ray.

CONCLUSIONS

Although very rare, intraosseous schwannoma should be taken under consideration in the differential diagnosis of benign-appearing osseous tumor in the proximal humerus with pathologic fracture.

First-ever intraosseous ancient schwannoma of the proximal ulna successfully treated using the cement technique

Schwannoma or neurilemmoma is a common soft tissue neoplasm arising from the neural sheath of Schwann cells. However, intraosseous schwannoma is rare, accounting for less than 0.2% of primary bone tumours. Several variants of schwannoma have been reported; among them, intraosseous schwannoma with ancient change is extremely rare. This current report presents an extremely rare case of ancient intraosseous neurilemmoma. The patient presented with right elbow pain and disability. A radiolucent, well-defined, lobulated lesion with a thin sclerotic rim in the proximal ulnar metaphysis that had caused a pathological fracture was noted. The mass was surgically excised using marginal resection and bone curettage was undertaken. The bone deficit was grafted with hydroxyapatite and β-tricalcium phosphate and augmented with bone cement. There were no signs of any recurrence after 3 years. This is the first case of an ancient intraosseous schwannoma of the proximal ulna. Although rare, intraosseous schwannoma should be considered in the differential diagnosis of radiographically benign-appearing osseous tumours in the bone. The cement technique is recommended for the treatment of intraosseous schwannoma.

Intraosseous schwannoma of the glenoid: case report and literature review

Intraosseous schwannomas represent an extremely rare subgroup of schwannomas, accounting for <1% of all primary bone tumors. They mostly occur in the mandible, the maxilla, the sacrum, and they are also seen in long bones. We herein report a rare presentation of an intraosseous schwannoma in the glenoid of a 49-year-old patient. She complained of shoulder pain and was referred to the orthopaedic oncologist after detection of a suspicious lesion on imaging. Biopsy revealed benign spindle cells and immunohistochemistry was positive for S100. Because of the rarity of these intraosseous schwannomas it is important to recognize their radiological and histological features and make a differential diagnosis with other lytic tumors. Only if these characteristics are recognized, correct treatment can be given with definite curettage and bone grafting and correct follow-up with avoidance of unnecessary adjuvant therapy.

An Unusual Localization of Intraosseous Schwannoma: The Hamate Bone

Intraosseous schwannoma of the hamate bone presented in this case is a very rare benign tumor, and its diagnosis combined with clinical, imaging and needle biopsy is important to guide further therapy. The diagnosis of schwannoma of the hamate was proved histologically following its surgical treatment by curettage.