Gorham's disease is a rare bone disorder characterized by bone loss (osteolysis), often associated abnormal blood vessel growth (angiomatous proliferation). Bone loss can occur in just one bone, or spread to soft tissue and adjacent bones. Symtoms may include pain, swelling, and increased risk of fracture. It may affect any part of the skeleton, but most commonly involves the skull, collarbone (clavicle), pelvis, ribs, spine, and/or jaw. Depending on the bones affected, various complications may occur. The cause of Gorham's disease is currently unknown. Most cases occur sporadically. Treatment is based on the signs and symptoms in each affected person, and most commonly involves surgery and/or radiation therapy. In some cases, Gorham's disease improves without treatment (spontaneous remission).

Complications from Gorham's disease may occur when fluids build-up in the space between the membrane that surround each lung and line the chest cavity (pleural effusion). This can have serious consequences, including loss of protein, malnutrition, and respiratory distress and failure.

Most people require intense treatment, especially if the disease has spread to other areas of the body or if there is extensive involvement in the spine and skull. Treatment options may include vitamin D and calcitonin supplements, radiation therapy, and/or surgery that may involve bone grafting. Some of the best outcomes reported have involved radiation therapy alone or in combination with surgery. Other treatments might include biphosphonates (such as pamidronate or zoledronic acid) and alpha-2b interferon. These treatments have led to improvement of symptoms in some cases. More research is necessary to determine the long-term safety and effectiveness of these therapies in people with Gorham's disease.

All treatments (pharmacological and surgical) are all still considered to be experimental since there have been no studies done to examine the effectiveness of anything used to date. In general, no single treatment has been proven effective in stopping the progression of the disease.

When just the limbs or pelvis are affected, there generally is no threat to life. However, pulmonary involvement with chylothorax (a type of pleural effusion) or spinal involvement (causing neurological complications) may mean a poor prognosis, and can even lead to death.

Gorham’s disease is very rare, and some cases may be misdiagnosed or undiagnosed. Because of this, it isn't known exactly how many people are affected. As of 2016, there is a discrepancy between the number of cases reported in literature reviews, ranging from 64 to 200 cases. However, there is consensus building that there are many more cases than have been reported. It may occur at any age, but is most often diagnosed in children and young adults. Some sources state that males are affected more often than females. Other sources state that the ratio is even.