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.