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Chondroblastoma of the femoral neck presenting with pathologic fracture: a case report

INTRODUCTION Chondroblastoma (CB) is a rare benign neoplasm of bone that accounts for nearly 1% of all bone tumors and usually occurs in the second decade of life. Long bones such as the proximal humerus, proximal tibia, and distal and proximal femur are themost frequent sites of CB involvement. Flat bones such as the patella rarely are involved. By radiograph, a well-defined lytic lesion in the epiphysis or apophysis of a growing child with an open epiphyseal plate is indicative of CB. However, in about one-third of patients, CB transverses the epiphyseal plate and affects the metaphysis. The primary involvement of themetaphyseal region without the involvement of the epiphysis is rare. Clinically, the most common presentation of CB is prolonged pain in the area of the lesion and occasionally in the adjacent joint. Presentation of CB as a pathologic fracture is very rare and scarcely has been reported in the literature. CB of the femoral neck presented with a pathologic fracture has been reported in only one previous study. Here, we report a case of CB of the proximal femur in a 9-year-old girl that was featured with several peculiar characteristics, such as the involvement of the metaphyseal region and presentation of pathologic fracture, making a differential diagnosis difficult. Informed consent for publication of the case was obtained from the patient’s parent. Institutional review board approval was not required for this case report.