A giant cell tumour (sometimes called an osteoclastoma) is a type of bone tumour.

Bone tumours can be divided into two main groups: primary and secondary. Primary bone tumours are those which start in the bones, secondary bone tumours are growths which are made up of seedlings of cancer which have come from cancerous tumours elsewhere in the body and spread to the bones.

Secondary bone tumours are very common whereas primary bone tumours are very uncommon.

Giant cell tumours are one type of primary bone tumour.

Giant cell tumours are most often seen in young adults. They are slightly more common in women than men.

Giant cell tumours usually develop in the long bones of the leg or arm. About 3 out of 4 will involve the area around the knee joint.

These tumours usually first appear as swellings on the bone which are often painful. Sometimes they can actually weaken the bone sufficiently to cause it to break.

Giant cell tumours of the bone are almost always benign (non-cancerous). But if they are not completely removed they have quite a strong tendency to grow back again. When this happens the new growths can sometimes develop as cancers rather than benign tumours.

The usual treatment for these tumours is surgery, to remove them completely. If the tumour is in a bone where an operation is particularly difficult then a course of radiotherapy can be used as an alternative.

As these tumours are benign, then if they are cleared by the initial operation then this results in a cure.