Gray-scale and Doppler characteristics of fibrous cortical defects in a child.

We report the case of a 9.5-year-old boy who underwent sonographic and radiographic examinations because of knee pain. Two fibrous cortical defects were discovered, in his right femur and left tibia; the femoral lesion was seen more easily on sonography than on radiography. On gray-scale sonography, the lesions were characterized as a scalloped indentation of the cortical surface containing hypoechoic soft tissue. On color Doppler sonography, discrete vessels were found at the periphery and within the substance of the lesions, and on spectral Doppler analysis, low-resistance arterial flow was detected in those vessels. Follow-up examinations performed 10 and 19 months after our initial examination showed signs that the lesions were healing. The diagnosis of fibrous cortical defect was suggested by the gray-scale and Doppler sonographic characteristics and confirmed on radiography. Although radiography is required to document these lesions if found incidentally on sonography, follow-up examinations using only sonography may be feasible.