Causes of Chondroblastoma
The cause of chondroblastomas is not known. The tumors are thought to arise from the growth plates at the ends of the bones, near joints. However, chondroblastomas do not produce the same type of normal cartilage that makes up the growth plates or surrounds and protects the joints.

There has been no proven connection between the development of the tumors and exposure to chemicals or radiation or any particular activities.