Massive Gorham-Stout syndrome of the pelvis.

Gorham-Stout disease is defined as a spontaneous, massive, and nonfamilial idiopathic osteolysis. The diagnosis is based essentially on radiological and histological findings. Biopsy reviews always reveal excessive intraosseous nonmalignant proliferation of small vessels, which results in bone resorption and may extend to adjacent bones and soft tissues. These lesions are progressively replaced by extensive fibrosis. Since its first description in 1955, there is still controversy about its prognosis, etiology, and treatment. A case of Gorham-Stout disease, located on the right pelvis, is reported with 50 years of clinical and radiographic follow-up, in a man who has never been treated. To date, this is the longest documented case report of the disease and its rare natural history. It demonstrates that after a variable time of evolution, the massive osteolysis is able to undergo spontaneous arrest and that the lesions may remain stable during several decades. Besides, no reossification was observed, even after 37 years of disease quiescence. Based on a large review of the literature, the authors then discuss the prognosis, etiopathology, and different therapeutic options available to halt the progression of the osteolysis.