What is a chondroblastoma?
Chondroblasts are specialized, cartilage-producing cells. Sometimes, these cells can grow out of control and cause a benign (non-cancerous) tumor known as a chondroblastoma. The cause of this tumor is unknown and is being researched. Chondroblastomas are usually found in the ends of long bones, such as the thigh bone (femur), upper arm bone (humerus), or shin bone (tibia). Sometimes they develop in the pelvis or hip socket. The vast majority of these tumors occur around the knee.
Although a chondroblastoma is considered a benign tumor, it has the potential to spread (metastasize) to the lungs. Metastasis is rare, occurring in less than 1 percent of cases. The tumor can cause pain, inflammation, joint stiffness, limping, and other symptoms. It appears more often in boys than girls, usually during their teenage years.
Treatment is usually successful, and usually involves surgery. Kids typically feel better soon afterward. Chondroblastoma can recur; the rate of recurrence is up to 20 percent.
Chondroblastoma | Symptoms & Causes
What are the symptoms of chondroblastoma?
While symptoms may vary from child to child, the most common include:
- ongoing pain, usually severe, in the affected area
- joint stiffness
- decreased range of motion
The symptoms of chondroblastoma may resemble those of other medical problems. So, it’s important that your child be evaluated by a doctor to obtain an accurate diagnosis.
A bone tumor should be treated quickly and correctly — the sooner a chondroblastoma is diagnosed and treated, the better the chances for a successful removal of the tumor.
Although complications after surgery for chondroblastomas are relatively uncommon, they can occur and can include:
- post-surgery complications, including infection, and damage to blood vessels or nerves
- early arthritis
- premature growth plate closure (for children with open growth plates)
What causes chondroblastoma?
The cause of this type of tumor is unknown.
Chondroblastoma | Diagnosis & Treatments
How is chondroblastoma diagnosed?
Doctors use some combination of the following techniques to diagnose chondroblastoma:
- physical exam
- MRI (magnetic resonance imaging)
- computed tomography scan (CT, CAT scan)
- bone scan
- biopsy or tissue sample from the tumor
What are the treatment options for chondroblastoma?
Specialists usually treat chondroblastoma with surgery. The tumor often occurs near a joint, making it a challenge to remove. Your child's physician will determine a specific course of treatment based on several factors, including:
- your child's age, overall health, and medical history
- the location and size of the tumor (including whether a joint is involved)
- the risk of fracture from bone weakness
- whether the disease has recurred
Prompt medical attention and aggressive therapy are important in minimizing any possibility of the tumor spreading. Continuous follow-up care is essential because chondroblastomas have up to a 20 percent chance of recurring after successful removal.
Treatment aimed at removing the tumor and preventing damage to the end of the affected bone usually involves a surgical procedure, such as:
- curettage and bone grafting: This is the most common treatment for chondroblastomas. During this procedure, the tumor is scraped out of the bone with a special instrument called a curette that has a scoop, loop, or ring at its tip. The remaining cavity is usually filled with donor bone tissue (allograft), bone chips taken from another bone in the child's body (autograft). The graft takes two or three months to heal into the bone.
- biopsy: During the operation, doctors will take a tissue sample of the tumor so that they can confirm the diagnosis under a microscope.
- extended curettage: In some cases, our orthopedic surgeons perform an “extended” curettage using a special instrument to remove additional layers of cells around the chondroblastoma. This is done to reduce the risk of recurrence.
- en bloc resection: Doctors may need to surgically remove bone containing the tumor if the tumor is located in the pelvis or certain other sites. They may insert pins and other hardware (internal fixation) to restore the structural integrity of the bone. If the tumor is in a hard-to-reach location, doctors may prefer to perform this procedure, in which radio frequency waves pass through a probe to kill the tumor cells by heating them to a high temperature. This procedure has the benefits of being minimally invasive and requiring less recovery time.
Chondroblastomas can return after treatment up to 20 percent of the time. To monitor the possibility of recurrence, we see children for follow-up care after surgery and treatment every three months for the first two years after treatment.
A typical follow-up visit may include:
- a physical exam
- imaging scans
A recurrent chondroblastoma is usually treated using the same techniques described above, although your child's orthopedic surgeon may opt for a more aggressive treatment to prevent further recurrence.
What is the long-term outlook?
The long-term outlook for a child who's been treated for chondroblastoma depends in part on:
- the extent of the disease
- the presence or absence of metastasis to the lungs
- the size and location of the tumor
- the tumor's response to therapy
- the age and overall health of your child
- your child's tolerance for specific medication, procedures, or therapies
Generally, surgery usually successfully treats a chondroblastoma that is caught before metastasis (spreading). Prompt medical attention, aggressive therapy, and regular follow-up care are important for the best long-term outlook. With these, your child should be able to walk and run normally, and to engage in sports and physical activities.
How we care for chondroblastomas
The experts in our Bone and Soft Tissue Tumor Program are devoted to caring for children and teenagers with chondroblastoma. We take an in-depth, multidisciplinary approach to care that ensures that your child receives a personalized treatment plan — as well as supportive care before and after his treatment. For your child’s care, we draw on the expertise of specialists such as:
- pediatric orthopedic and general surgeons who are nationally recognized for their expertise in removing bone and soft tissue tumors
- pediatric experts from every needed medical subspecialty, including pathology, radiology, physical therapy, and bracing/casting
- experienced pediatric nurses
- Child Life specialists, psychologists, social workers, and resource specialists