Pediatric extraskeletal osteosarcoma.

Extraskeletal osteosarcoma (ESOS) is a rare malignant tumor composed of mesenchymal cells comprising approximately 1% of soft-tissue sarcomas and 4% of all osteosarcomas. Primary osseous osteosarcomas more commonly develop in children and adolescents, but there are very few reports of ESOS occurring in those younger than 40 years. These variants of high-grade osteosarcoma are often characterized histopathologically by the production of an osteoid matrix and bone from malignant osteoblasts that by definition are present in the soft tissue outside the normal skeletal anatomy. We present a 13-year-old girl with a gradually enlarging, painless left thigh mass.

Developmental venous anomalies and cavernous angiomas: a review of the concurrence, imaging, and treatment of these vascular malformations.

Deep venous anomalies and cavernous angiomas are two distinct intracranial lesions. Although these lesions can be found in association with each other, they have different pathologic characteristics and developmental mechanisms. These lesions can produce a variety of clinical symptoms or in some cases can be asymptomatic. The management of these anomalies can include conservative measures in some cases and aggressive intervention in others. Several imaging modalities can be used to evaluate these distinct lesions and often more than one are needed for a prompt and reliable diagnosis. Because of the tendency of these lesions to occur simultaneously, thorough evaluation of these anomalies and their surrounding tissues is critical in their clinical management. In this review, the characteristics and radiographic evaluation of these lesions will be presented and the therapeutic options for these anomalies will be discussed.

Hemophilic pseudotumor.

Bleeding diatheses are a hallmark of hemophilia. Hemophilic pseudotumor results from multiple episodes of hemorrhage into bones or soft tissue spaces. It is uncommon and is seen in severe cases of hemophilia only 1-2% of the time. Complications and symptoms arise due to pain and/or compression of surrounding structures. Pathologic fractures can be associated with intraosseous lesions and can result from bone destruction or resorption due to the chronic pressure of an osseous hemorrhage. Radiographs may demonstrate expansile lesions of the bones or increased soft tissue density that may be associated with extra osseous lesions. Bleeding may also occur within the joint space. These intra-articular hemorrhages can, over time, result in hemophilic arthropathy. The following case report demonstrates both an expansile lesion of a metacarpal as well as hemophilic knee arthropathy in an 11 year old.