1. The clinical and pathological features are given of an example of the rare syndrome of progressive and massive osteolysis associated with haemangiomatous changes in the bones affected.

2. Twenty-six cases have been previously reported, but this is only the second from Britain. Only one other patient is considered to have died as a direct result of the disease.

The characteristics of enchondromata of long bones are mentioned and the special features of a malignant chondroma of the calcaneum are described. The management of such a case is discussed.