Chondroblastoma is a benign rare tumor of cartilaginous origin composed of chondroblasts.
Its peak incidence is in individuals between 10 and 20 years of age. It is more common in males, with a male-to-female ratio of 2:l.
Chondroblastoma involves the epiphysis, the apophysis, or both but may extend into the metaphysis after destroying the growth plate.
CT accurately demonstrates the extent of the lesion as well as matrix calcifications and subtle cortical infractions. Extension through the growth plate, however, is best detected with conventional tomography or MRI because the growth plate is usually best visualized in the sagittal or coronal plane. Both TI-weighted and T2- weighted MR images demonstrate a peripheral rim of signal void that corresponds to the sclerotic margin of the lesion. Abnormal signal intensity in large areas of bone marrow surrounding the lesion has been seen and probably represents bone marrow edema.