[The importance of case reports as compared to evidence-based medicine and molecular explanation].

Over the past few decades case reports have become a much maligned form of medical research. Does the case report still have a place in modern medical science, which is based on evidence-based medicine on the one hand and genomics on the other? The answer is an emphatic 'yes': clinical case descriptions form a necessary basis for detecting new ideas--new disease entities, new aetiological clues, side effects and new treatments. They are also necessary in medical education, and are a time-honoured cornerstone of quality assurance: the clinical pathological conference where difficult or rare cases are discussed for the benefit of all. Case reports form the basis of progress in clinical science, independent of basic subjects or epidemiological insights. They will continue to be necessary in a context of discovery. Moreover, they can also provide convincing clinical evidence. Finally, a well-written case report must clearly state what is already known and what the case report adds to this.