Contour irregularities of the distal femur caused by developmental, traumatic, and benign cortically-based neoplastic conditions: radiographic and MRI correlation.

This review illustrates the radiographic and magnetic resonance imaging (MRI) appearances of a variety of entities that result in surface contour abnormalities of the distal femur. Such abnormalities may result from developmental variants expressed in the growing skeleton, from trauma, or from cortically-based tumours. As the number of MRI examinations of the knee performed annually to exclude internal derangement increases, the frequency with which these variants and pathological entities are encountered will likewise increase. In most cases, the location of the lesion, as well as its specific imaging characteristics, will allow an accurate diagnosis.