Gorhams disease (pronounced GOR-amz), also known as Gorham vanishing bone disease and phantom bone disease, is a very rare skeletal condition of unknown cause, characterized by the uncontrolled proliferation of distended, thin-walled vascular or lymphatic channels within bone, which leads to resorption and replacement of bone with angiomas and/or fibrosis. Signs and symptoms
The symptoms of Gorhams disease vary depending on the bones involved. It may affect any part of the skeleton, but the most common sites of disease are the shoulder, skull, pelvic girdle, jaw, ribs, and spine.In some cases, no symptoms are seen until a fracture occurs either spontaneously or following minor trauma, such as a fall. An acute onset of localized pain and swelling may occur. More commonly, pain of no apparent cause increases in frequency and intensity over time and may eventually be accompanied by weakness and noticeable deformity of the area. The rate of progression is unpredictable, and the prognosis can be difficult. The disease may stabilize after a number of years, go into spontaneous remission, or in cases involving the chest and upper spine, prove fatal. Recurrence of the disease following remission can also occur. Involvement of the spine and skull base may cause a poor outcome from neurological complications. In many cases, the result of Gorhams disease is severe deformity and functional disability.Symptoms such as difficulty breathing and chest pain may be present if the disease is present in the ribs, scapula, or thoracic vertebrae.
Gorham and others speculated that such a change in the bone chemistry might cause an imbalance in the rate of osteoclast to osteoblast activity such that more bone is dissolved than is replaced. Beginning in the 1990s, elevated levels of a protein called interleukin-6 (IL-6) being detected in people with the disease were reported, leading some to suggest that increased levels of IL-6 and vascular endothelial growth factor (VEGF) may contribute to the chemical changes Gorham and others believed were the cause of this type of osteolysis.In 1999, Möller and colleagues concluded, "The Gorham-Stout syndrome may be, essentially, a monocentric bone disease with a focally increased bone resorption due to an increased number of paracrine – or autocrine – stimulated hyperactive osteoclasts. The resorbed bone is replaced by a markedly vascularized  fibrous tissue. The apparent contradiction concerning the presence or absence or the number of osteoclasts, may be explained by the different phases of the syndrome." They further stated that their histopathological study provided good evidence that osteolytic changes seen in Gorhams disease are the result of hyperactive osteoclastic bone. However, others have concluded that lymphangiomatosis and Gorhams disease should be considered as a spectrum of disease rather than separate diseases.While a consensus exists that Gorhams is caused by deranged osteoclastic activity, no conclusive evidence has been found as to what causes this behavior to begin.