My collection of how to use MDX in a SSAS 2012 / 2014 environment.
When you have a CASE WHEN in MDX you basically have two options:
The Simple or Searched statement:
CASE [<<Set To Be Evaluated>>] WHEN [<<condition1>>] THEN [<<action>>] WHEN [<<condition2>>] THEN [<<action>>]
CASE [<<Set To Be Evaluated>>]
WHEN [<<condition1>>] THEN [<<action>>]
WHEN [<<condition2>>] THEN [<<action>>]
ELSE [<<action>>] END