Have you ever heard of a disappearing bone disease? My sister just emailed me that she has this -- what is it?

Disappearing bone disease is also known as phantom bone disease, vanishing bone disease, or Gorham's disease. It was first described by a doctor by the name of Gorham back in 1954.

There isn't much that's really known about this condition. It is a rare disease that usually affects the bone of the arms or legs. Most often, only one bone is involved. It can spread to nearby soft tissues and the next closest bone.

The condition is caused by a build-up of blood vessels within the bone. The result is massive osteolysis or the disintegration of large amounts of bone. The bone is replaced by fibrous tissue. Fractures are common and can lead to loss of function and disability.

The cause of Gorham's disease is unknown. A genetic link is suspected. Treatment does not stop the process. Generally, people affected by Gorham's Disease take Vitamin D, calcium, and drugs such as bisphosphonates to help stop the bone destruction. Pain relievers and antiinflammatories are used when there is pain.