Chondroblastoma

Introduction
A benign chondrogenic lesion  Age & location epiphyseal lesion in young patients (usually around 12 years of age)  common locations include distal femur, proximal tibia, proximal humerus, proximal femur, and apophysis or triradiate cartilage of the pelvis typically epiphyseal but may occasionally cross the physis Genetics may have genetic abnormalities on chromosome 5 and 8 Prognosis 2-5% of benign chondroblasts metastasize to the lungs (similar to giant cell tumor in this respect)

Symptoms

Presentation pain referred to involved joint Physical examination exam may show mechanical symptoms with limitations of motion

Imaging

Radiograph well-circumscribed epiphyseal lytic lesion with thin rim of sclerotic bone that is sharply demarcated from normal medullary cavity  lesions often cross physis into metaphysis mineralization within the lesion may or may not be present

Histology

Classic characteristics are chondroblasts arranged in "cobblestone" or "chickenwire" pattern may be present  occasional multinucleated giant cells may be present  loose myxoid tissue

Treatment

Operative extended intralesional curettage and bone grafting  may do local adjuvant treatment with phenol or cryotherapy