Consider cases you find interesting of unique. Many common conditions can be interesting to you. You are not expected to report on a ‘once in a lifetime’ case. In fact, we don’t generally recommend that you focus on a rare event. Common presentations are interesting because they can highlight the use of evidence to make decisions. It gives you (and readers) an opportunity to reflect on patient management and decision-making.
Consider clinical evidence or guidelines that you find new, exciting, interesting, or important - perhaps a new drug or new diagnostic procedure. Then think about cases where the new drug or new diagnostic procedure might be relevant. You case report would evaluate the relevance of this new evidence for that case.
Case reports can include cases where things went well (good news), or where things did not go well (bad news) but usually they are mixed in terms of message. Remember that many of the best case reports are those that report on mistakes, misinterpretations, and/or unintended consequences. Many case reports highlight the challenge of applying the evidence to a specific case and focus on the uncertainty rather than a definitive solution. They often focus on how clinical opinion and patient wishes are mixed with clinical evidence.
