Throwing a mitk::Exception inside the itk processing pipeline (e.g. GenerateData() of an filter) results in catching of the exception in itkProcressObject as an itk::ExceptionObject. The mitkException is not passed furtheron, but is thrown as an itk::ExceptionObject, what results in catching of an unknown exception during application of the class (e.g. in an unit test).
The supposed reason for that is that the mitk:: Exception inherits from itk::ExceptionObject, since it is caught as an itk::Exception.
This unexpected catching of the exception makes the exception handling on the application side impossible. The inheritance from itk::ExceptionObject should hence be reconsidered.