Introduction

Bone tumors are growths of abnormal cells in bones.

Bone tumors may be noncancerous (benign) or cancerous (malignant). Noncancerous bone tumors are relatively common, but cancerous ones are rare. Also, bone tumors may be primary--noncancerous or cancerous tumors that originate in the bone itself--or metastatic--cancerous tumors that originate elsewhere in the body (for example, in the breast or prostate gland) and then spread to bone. In children, most cancerous bone tumors are primary; in adults, most are metastatic.

Bone pain is the most common symptom of bone tumors. The pain can be severe (somewhat like a toothache, which is also a form of bone pain). In addition, a lump may be noticeable. Sometimes a tumor, especially if cancerous, weakens a bone, causing it to fracture with little or no stress (pathologic fracture).

A persistently painful joint or limb should be x-rayed. However, x-rays tend to show only that there is an abnormality suggestive of an abnormal growth, usually without indicating whether a tumor is noncancerous or cancerous. Computed tomography (CT) and magnetic resonance imaging (MRI) often help determine the exact location and size of the tumor and give additional information as to the nature of the tumor, but these tests rarely provide a specific diagnosis.

Usually, removing a tissue sample of the tumor for examination under a microscope (biopsy) is necessary for diagnosis. For many tumors, a sample may be taken by inserting a needle into the tumor and withdrawing some cells (aspiration biopsy); however, because the needle used is very small, sometimes normal cells may be sampled and cancer cells missed, even when cancer cells are lying right beside the normal cells. Sometimes, a surgical procedure called open biopsy is necessary to obtain an adequate sample for diagnosis.