In defense of case reports and case series.

Case reports and case series have their own role in the progress of medical science. They permit discovery of new diseases and unexpected effects (adverse or beneficial) as well as the study of mechanisms, and they play an important role in medical education. Case reports and series have a high sensitivity for detecting novelty and therefore remain one of the cornerstones of medical progress; they provide many new ideas in medicine. At the same time, good case reporting demands a clear focus to make explicit to the audience why a particular observation is important in the context of existing knowledge.