Carcinomata. Cancer of bone always is secondary to cancer in some epithelial organ. The infection may take place by direct extension through the blood or the lymphatics.

In cases of metastatic invasions of bone, spontaneous fractures oftentimes are the first symptom which calls attention to the fact that metastases have occurred.

Treatment. As in other malignant tumors, the indication is for absolute and radical removal whenever possible. Unfortunately, this very seldom can be done, because at the time the bone has become affected by extension to any great degree, radical operation is impossible. Many times, however, extensive operations must be undertaken for the removal of bone.