An osteoid osteoma is a benign, bone-forming tumour that occurs most often in the long bones of the lower extremities.
The femur (thighbone) is the most common location of occurrence, although it can emerge in the bones of the hand and it sometimes occurs in the lower part of the spine. Osteoid osteomas are very small tumours that do not grow larger that half an inch in diameter.
They usually emerges sometime during the teenage years or early adulthood. The condition seems to occur more often in males than females. These tumours, while causing painful symptoms, typically do not progress or harm the host bone, although in young children, those located near a growth plate, may deform the host bone, or stimulate the bone to grow larger or longer. They do not, however, metastasise (spread) beyond the bone. If located near a joint, they may be associated with swelling or fluid in the joint.
What causes an Osteoid Osteoma?
An osteoid osteoma occurs when certain cells divide uncontrollably, forming a small mass comprised of bone and other tissue. This growing tumour replaces healthy bone tissue with abnormal, hard bone tissue. No one knows exactly why this occurs.
What are the symptoms of Osteoid Osteoma?
The following are the most common symptoms of an osteoid osteoma. Keep in mind that each individual may experience symptoms differently:
The signs and symptoms of osteoid osteoma may resemble other medical conditions or problems. Occasionally children with undiagnosed osteoid osteomas have been thought to have a psychological or psychiatric condition. Always consult a physician for a diagnosis.
How is Osteoid Osteoma diagnosed?
In addition to taking a complete physical and performing a full medical examination, your child's doctor may use any of the following tests (alone or in combination) to diagnose osteoid osteoma:
How is an Osteoid Osteoma treated?
Specific treatment for an osteoid osteoma will be determined by your child's physician based on:
Treatment for osteoid osteoma traditionally involved an operation to remove the tumour performed by an orthopaedic surgeon. More recently, many osteoid osteomas have been treated by the radiologist using the technique known as percutaneous radiofrequency ablation. This is a minimally invasive procedure in which radio frequencies are passed beneath the skin through a needle to kill the tumour cells by heating them to a high temperature. This technique is performed by the radiologist in a CT scan under general anaesthesia. The advantage is that this is a day procedure that does not significantly weaken the bone. It quite successfully cures the tumour and relieves the pain and has much less morbidity than an operation. This method cannot be used to treat tumours of the spinal column, but in other locations has largely replaced operations.
In some cases, if the doctor determines that heat ablation cannot be used to treat your child's osteoid osteoma (i.e. if the tumour is in the spinal column) than your child may need an operation. In most cases, surgery alone, without complimentary therapies, is all that is necessary.
The following surgical procedures are among those used to treat osteoid osteoma:
What is the long-term outlook for a patient with an osteoid osteoma?
Prognosis for an osteoid osteoma is generally excellent, although prognosis varies from individual to individual depending on: how active the tumour is:
Most of these tumours can be successfully treated. However, recurrence can occur. Continuous follow-up care is essential for the successful treatment of an osteoid osteoma. A schedule of follow-up care should be determined by your child's physician and other members of your care team to monitor ongoing response to treatment and possible late effects of treatment.