A 9-year-old active girl presented to physical therapy via direct access with intermittent severe pain deep in the distal third of her left thigh that had a 2-year history. Twenty months prior, her pediatrician ordered radiographs that were noncontributory and diagnosed her with "growing pains." During examination, an osseous nontender enlargement of the femur was found proximal to the patella, and the patient was referred to her pediatrician for imaging. Radiographs demonstrated an expansile bone lesion with a mixed matrix and an open surgical biopsy determined the mass to be consistent with nonbacterial osteomyelitis. .