Chondromyxoid Fibroma (CMF) is one of the rarest bone tumors. It represents less than 1% of the bone tumors that are diagnosed. Most pediatric patients who get CMF are teenagers. CMF is a benign (noncancerous) tumor.
CMF is made of cartilage, which is the smooth lining over your joints that allow them to move smoothly. It occurs nears the ends of bones such as the femur (the thigh bone), the tibia (the shin bone) and the calcaneus (the heel bone). CMF does not spread to other parts of the body.
We do not know what causes CMF.
CMF may first be noticed when the parent or patient feels a bony lump or swelling. There may be some pain or no pain.
Your doctor will talk to you and your child about his or her medical history as well as any symptoms. He or she will ask about any history of trauma or a fall, any pain, pain with activities, or pain during the night.
Your doctor will see if there are any bony lumps, and whether those areas are painful. He or she will also check how the motion is in the joints near the area.
X-rays – X-rays are used to look at the bone and the tumor. CMF looks like a small round or oval bubble that appears on the edges of the bone.
CT scan or MRI - These tests helps to show whether the tumor is growing into the soft tissues around the bone and also helps to show how much of the bone is involved. CT and MRI also help to tell whether the tumor is benign, such as a CMF, or whether it is another type of tumor that might be more aggressive like cancer.
While these studies can help to guide the diagnosis, there may still be other things that the lesion can be.
Despite getting X-Rays, a CT scan, and an MRI, the diagnosis of CMF cannot make made completely unless the tissue is examined under a microscope. In order to obtain that tissue, your surgeon will need to biopsy the lesion. For most children, this involves going to the operating room. While your child is completely asleep with anesthesia, your surgeon will take a sample and look at it under the microscope with a pathologist.
Curettage can be done at the same time of biopsy, if the surgeon and pathologist are able to establish a diagnosis of CMF under the microscope. This involves scraping the tumor out of the bone with special tools. To fill the hole, your surgeon may place bone graft, which can either be bone from your child’s own body, bone from another person, or a bone graft substitute that is made in a lab. Sometimes, your surgeons may also put a chemical in the hole to try to prevent the tumor from coming back. However, it is possible for this tumor to come back, even after surgical treatment to remove it. The tumor returns in about 25% of cases.
Depending on where the tumor is, your surgeon may not be able to remove it completely, especially if it is near the growth plate and may cause permanent problems with the bone growing.
Your surgeon will most likely continue to follow you for several years to make sure the tumor does not return. If it does, the treatment options remain similar.
No, it is not cancer. The word “tumor” refers to any sort of abnormal growth in bone, muscle, or soft tissue. “Benign” means that the abnormal growth is a collection of normal tissue.
Q. If we remove it, will it come back?
The chance of the tumor coming back depends on the type of tumor. Solitary osteochondromas and non-ossifying fibromas have a very low risk of recurrence after complete removal. Even though they are benign tumors, unicameral bone cysts and chondromyxoid fibromas have a high risk of recurrence even after they are treated surgically. However, the risk of it coming back decreases once your child stops growing.
Q. Will the tumor grow in size as my child grows?
It is possible that the tumor may grow proportionally with your child grows, but this usually stops when your child stops growing.
Q. Why does my doctor need to get an X-ray, a CT scan, AND an MRI? This seems like a lot of studies.
Each study shows something different. X-rays are fast and easy to get, and many tumors can be diagnosed from just the way it looks on the X-ray. However, X-rays only show bone and do not show soft tissue details. Also, it can be difficult on X-ray to see the full extent of the tumor. The CT scan shows bony detail very well, and gives cross-sectional images that can help with surgical planning. MRI is used to look at the soft tissues and it can show whether the tumor is affecting any of the surrounding muscle or tissues. Your doctor will determine which of these studies are appropriate for your child.
Q. Can my child play sports?
Yes, your child may continue to play sports. However, the risk of the bone breaking through the area of the tumor increases if the size of the tumor is more than half the width of the bone. Your doctor will provide advice about the safety of sports.