[Primary malignant bone tumours-part 1].

Primary malignant bone tumours are rare (about 0.2% of all malignancies) whereby-according to age-both osteosarcoma and Ewing's sarcoma are the most frequent bone sarcomas in children and adolescents. Both sarcomas are highly-malignant tumours with poor prognosis (Ewing's sarcoma) in particular when metastasized (osteosarcoma). There is a broad diagnostic armamentarium available, allowing precise detection of such tumours. However, alertness and familiarity of (early) radiological signs (such as periosteal reactions) are prerequisites to arouse suspicion. Radiological methods (plain radiography, magnetic resonance imaging [MRI], computed tomography [CT], ultrasonography) will be discussed regarding their pathomorphological clues. Likewise, both use and significance of more advanced imaging modalities (dual-energy CT, photon-counting CT; the Dixon technique and MRI with ultrashort time-to-echo [TE] sequences) are reviewed.