[Skeletal changes due to bone metastases : Morphology and selected differential diagnoses]

The detection or exclusion of bone metastases is one of the most frequent tasks faced by the radiologist. The decision has significant and long-term consequences for the patient, therapeutic decisions and prognosis. For these reasons, specialized knowledge of the morphology, diagnostics and differential diagnoses of skeletal metastases is essential for the radiologist.

The various manifestations of skeletal metastases are elaborated and some representative nonmetastatic differential diagnoses are presented.

The way in which metastases are radiologically depicted depends on the primary tumor, the localization of a metastasis, the interaction between metastasis and host bone, concomitant diseases, already initiated treatment and the individual circumstances of the patient. The basis of radiological diagnostics is still projection radiography, albeit with limitations. Computed tomography (CT) and magnetic resonance imaging (MRI) are firmly established methods in diagnostic imaging. Invasive diagnostics, preferably a CT-guided biopsy, are frequently unavoidable.

Various radiological procedures form the basis of the diagnostics of bone metastases. In many cases a definite diagnosis, i.e. presence or absence of bone metastases, is possible. In cases in which a suspected diagnosis with justified differential diagnoses arises, the radiologist, referring physician and other specialists to be consulted should advise on the benefits, risks and therapeutic consequences of an invasive procedure, usually by CT-guided biopsy.