A 40-year-old man, with no medical history of note, came to see us with a dent in his head
. He had noticed the asymmetry about 5 years before, and it had increased progressively ever since. On examination, the scalp was normal. CT of the head showed massive destruction of bone, within a well defined area. A technetium-99m methylene diphosphate bone scan showed increased metabolic activity at the edges of the area. These findings were consistent with Gorham’s disease—a rare idiopathic disorder in which one or several bones are destroyed and replaced by connective and vascular tissue. Gorham’s disease of the ribs or thoracic vertebrae can lead to chylothorax and life-threatening respiratory failure. Radiotherapy and surgery are the main therapeutic options.