Cystic fibrous dysplasia of the humerus.

The patient was a 39-year-old woman with a 3-month history of worsening right distal humerus pain that was insidious in onset. At the time of the initial physical therapy visit, the patient complained of weakness and numbness throughout the entire right upper extremity, with an inability to perform daily activities. Magnetic resonance imaging revealed extensive bone marrow signal abnormalities extending from the proximal humeral epiphysis to the distal humeral diaphysis. Further evaluation with radiographs and computed tomography revealed multiple lytic lesions through the humerus. Tissue biopsy confirmed a diagnosis of cystic fibrous dysplasia.