[The x-ray morphology of chondromyxoid fibroma]

29 cases of chondromyxoid fibroma (CMF) from the material submitted to the Bone Tumour Register in Münster were reviewed. The tumour was observed most frequently in the second and third decades of life, with a slight female preponderance in our series. The diaphyseal and metaphyseal regions of the lower limb were most commonly affected, with a particular predisposition for the knee. The lesions were located eccentrically in 71% showed cortical expansion in 72%, and pseudotrabeculation in 51% of cases. The lytic patterns were classified as Lodwick IA in 35%, as Lodwick IB in 45%, as Lodwick IC in 17% and as Lodwick II in 3% of cases. Due to the absence of characteristic radiographic features, the differential diagnosis from aneurysmal bone cyst, giant cell tumours and non-ossifying fibroma is often difficult. Radiographic findings would however indicate benignity and, therefore, help to differentiate the lesion from chondrosarcoma, to which it bears strong histological similarity.