en جراحی زانو Knee surgery Gorham-Stout syndrome is a rare disease, which results in spontaneous bone resorption. Failure to proper diagnosis of this syndrome can lead to unnecessary bone surgeries. A 13 years old girl with right hip pain, limping, and proximal femur lytic lesions underwent three surgeries without the exact diagnosis. Surgical curettage, bone graft, and internal fixation failed miserably. According to the imaging studies and the biopsy results of bone lesions that showed lymphangiomatosis, accompanied by skin and spleen lesions, a rare presentation of the Gorham-Stout syndrome was diagnosed. Bisphosphonate treatment provides a significant recovery in her symptoms and imaging studies confirmed bone improvement. Gorham-Stout Syndrome,Lymphangiomatosis,Osteolysis 0 0 http://jros.iums.ac.ir/browse.php?a_code=A-10-39-152&slc_lang=en&sid=1 Mohammad Hassani 10031947532846004819 10031947532846004819 Yes Mashhad University of Medical Sciences, Mashhad, Iran Mohammad Javad Shariyate jshariyate@yahoo.com 10031947532846004820 10031947532846004820 No Mashhad University of Medical Sciences, Mashhad, Iran Shirin Taraz Jamshidi 10031947532846004821 10031947532846004821 No Mashhad University of Medical Sciences, Mashhad, Iran Mohammad Hallaj Moghaddam Hallaj Moghaddam 10031947532846004822 10031947532846004822 No Mashhad University of Medical Sciences, Mashhad, Iran Farzad Omidi-Kashani 10031947532846004823 10031947532846004823 No Mashhad University of Medical Sciences, Mashhad, Iran