Summary: | Introduction
Schwannomas are benign soft tissue tumors of neural origin, predominantly occurring in the head and neck regions due to their rich innervation. Intraosseous schwannoma (IOS) is an exceedingly rare form of schwannoma. This study aims to enhance the understanding of intraosseous schwannoma by reviewing cases affecting the upper extremity bones and providing a detailed analysis of their radiographic and magnetic resonance imaging (MRI) characteristics along with a review of the literature on these rare tumors.
Material and Methods
A total of three patients with IOS in upper extremity bones were identified and analyzed. Radiographs and MRI scans were available for all patients. A comprehensive literature review was conducted, including case reports, retrospective studies, and reviews of published data. The epidemiology, anatomical distribution, radiographic characteristics, histological findings, and therapeutic outcomes of intraosseous schwannoma were all investigated, identifying 31 documented cases of IOS involving extremity bones.
Results
Intraosseous schwannomas primarily affect the mandible, followed by the sacrum and vertebrae. Patients frequently present with non-specific symptoms such as localized pain, swelling, or neurological impairments, which can lead to delayed diagnosis. Radiographic evaluation of IOS typically reveals lytic lesions with well-defined, expansile features and thin sclerotic rims. MRI findings showed that IOS lesions appeared low to iso-intense on T1-weighted images and hyper-intense on T2-weighted images. These imaging characteristics are crucial for differentiating IOS from other lytic bone lesions. Histologically, the presence of Antoni A and Antoni B patterns, as well as S-100 protein positivity, confirms the diagnosis. Surgical management, consisting of curettage, provides a favorable prognosis and low recurrence rates.
Conclusion
Despite its rarity, intraosseous schwannoma should be considered in the differential diagnosis of well-defined, expansile lytic bone lesions, particularly those with thin sclerotic rims. This review provides the most comprehensive analysis to date of IOS affecting extremity bones, emphasizing the importance of recognizing this entity in clinical practice.
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