[Compact costal islands in the differential diagnosis of small coin lesions in chest x-rays].

The radiological characteristics of 13 costal bone-islands in 12 patients (one patient with bilateral bicostal involvement) are described. The bone-island manifests itself as a small dense coin-lesion following fluoroscopically the respirative movements of the host-rib. X-ray-films and a fluoroscopy confined to the interesting area allow an exact diagnosis. Retrospective analyses of X-ray-films generally reveal an unchanged existence over a long time period. No therapeutic consequences are necessary.