DOI: 10.36347/sjmcr.2017.v05i04.011

Pages: 261-264

A young man man who had knee pain was diagnosed as bone tumor at the distal end of the femur by non-contrast knee MR imaging. The mass lesion at distal lateral femoral condyle was interpreted as chondroblastoma in another facility. The patient underwent routine laboratory evaluations and contrast-enhanced MR imaging in our hospital. On MRI, leison was seen that there were findings of previous posterior horn meniscectomy at medial femoral condyle and a hyper-intense, heterogeneous, solid mass with subchondral, subcortical localization at the level of lateral condyle epiphysis which had lobulated contours extending to medulla with suspected septation. The localization, appearance, and size of the lesion suggested chondroblastoma. On contrast-enhanced images, it was recognized that the lesion didn't exhibit contrast-enhancement. When MR images were assessed in details, it was seen that there was a defective appearance at the cartilage of lateral femoral condyle. In the history, it was found that the patient underwent meniscus surgery 1.5 years ago. Cartilage injury had occurred during surgery, causing osteochondritis dissecans in bone tissue. We intended to emphasize that diagnosis will be facilitated by detailed history taking and meticulous radiological evaluation.