[Fibrous cortical defects (author's transl)].

During a period of two and a half years, twelve fibrous cortical defects were discovered as incidental findings. With the exception of two cases, the radiological findings remained unchanged during the period of observation. One large defect extending into the diaphysis was submitted to surgery and verified histologically. The characteristic radiological appearances and the differential diagnosis from similar looking benign and malignant bone abnormalities are discussed and compared with the findings of other authors.