Question

My father is 80 yrs old and was diagnosed with Paget's disease, following a year of severe pain in his knee. But subsequently another physician did another x-ray, and found a mass on the knee, that had destroyed a lot of the matter in the knee. He arranged for a biopsy, but the results of this are inconclusive and my father does not know whether or not he has a malignancy. He has been told that he will require knee replacement, and filling the area with some kind of material. Please could you explain what this all means.

Answer

Primary bone tumours are rare, and at your father's age it is much more common for any growth in the bone to be a secondary tumour (spreading from elsewhere in the body). So has your father had any other cancer? Certainly bone tumours can cause pain and it is not always easy to tell whether the tumour is benign (and therefore not likely to prove fatal), or malignant.

It is possible for certain conditions to mimic tumours, such as infection and stress fractures. It is therefore most important with any mass, and particularly one that has appeared recently (because previous x-rays did not show it), to know whether it is localised to one site, is associated with any systemic illness, is due to tumour growth, or something else. The treatment then depends on the lesion. If it is localised to one area it may well be possible to remove it. However, if the tumour has already eroded the bone, something will have to be placed in the area to pack it or there will be considerable shortening of the limb.

Paget's disease is characterised by enlargement and thickening of the bone, in bone with abnormal architecture. The bones are usually brittle. It is usually a condition associated with older men and women and most often it remains asymptomatic and is discovered accidentally when the patient is x-rayed for some other reason. When pain occurs, it is dull and constant and may be worse at night. The bones are soft and may therefore bend or fracture. Very occasionally there is tumour growth within Paget's.