Enchondroma

An enchondroma is a benign tumor found inside of bone. The typical scenario is that a patient had an x-ray for an injury to a joint, commonly the hand, shoulder, knee, or ankle. While the joint looks normal, an abnormality is seen inside the bone. Often these are completely unrelated to the cause of pain, and one of the most common reasons is an enchondroma.

An enchondroma is a type of tumor that causes the formation of cartilage cells within a bone. Usually, these tumours occur in the hand or in the long bones of the extremities including the humerus (arm bone), femur (thigh bone) and tibia (shin bone). It is the most common benign (not harmful) tumour seen in the hand.

As mentioned, most enchondromas behave without aggression. There is a related condition where the tumor can be malignant, called a chondrosarcoma. A low-grade chondrosarcoma (malignant cancer) can behave like an enchondroma, and vice versa. If patients do have pain that is coming from the tumor, or if the x-rays have the appearance of a more aggressive problem, then a low-grade chondrosarcoma should be considered as a possible diagnosis.

There is a syndrome called Ollier's Disease in which patients have many enchondromas. Patients with this condition are generally monitored more closely, as they are more likely to develop chondrosarcomas from what was previously an enchondroma.

Typically, no treatment is necessary for an enchondroma. Most abnormalities detected within the bone can be rechecked with normal x-rays over a period of time. If the tumor looks like an enchondroma, stays the same or goes away, then there is generally no need for ongoing surveillance. If the tumor starts to grow, shows signs of becoming more aggressive, it may be determined that the tumor needs to be treated more like a chondrosarcoma. Unfortunately, biopsy results can be very difficult to distinguish between a normal enchondroma and a low-grade chondrosarcoma, therefore treatment decisions are generally based on symptoms and radiographic findings, rather than on biopsy results.

Within the hand, enchondromas can weaken the bone sufficiently that a fracture occurs. When this happens, the injury is called a pathological fracture. The usual treatment of a pathologic fracture caused by an enchondroma in the hand is first to allow the broken bone to heal. This may stimulate the enchondroma to heal as well. If not, your surgeon may recommend a procedure to remove the tumor cells and place a bone graft in the bone the strengthen the bone and prevent re-injury.