Malignant bone tumors require the same careful staging as, for example
, lung cancer. However, well-established staging systems for non-osseo
us tumors are not suitable for bone tumors. Therefore we present Ennek
ing's staging system for malign bone tumors here, which is better adap
ted to the special problems of these entities because it integrates cl
inical, radiological and histological findings. The weak points of Enn
eking's staging system (e.g. inflexibility, changes in radiological mo
dalities in the past 20 years) are discussed.