While the case study and the case method are often confused and the terms used interchangeably, they actually are not the same thing. The difference becomes critical when considered in terms of learning.
A case study is a story about a situation or event that contains a problem or issue, usually a real situation. The case study usually contains information about the problem PLUS information about how the situation was addressed, and the results of the actions taken to solve the problem. For example, one might use a case study from Apple computers pertaining to leadership by describing the problems Apple faced with their original leadership, then discuss what was done (hiring a new CEO, Scully) to the results.
After reading the case study, learners might be asked to analyse the case, in essence, after the fact.
Did you now that the case method used extensively at business schools, and in particular, at the Harvard Business School, was originally introduced around 1910? It has been an established instructional method for a century.The case method also presents a situation or problem space, and need not be taken from real life. However, it does not tell the learners "what was done", and neither does it provide any solutions at all. It is up to the learners to generate possible solutions that might fit the case facts.
The latter is more involving for learners, and forces them into proactive problem-solving rather than posthoc analysis.