An outer diffuser case of a diffuser case assembly for use in a gas turbine engine may have a housing orientated about an engine axis, a forward flange projecting radially outward from the housing, a mid-flange spaced axially aft of the forward flange and projecting radially inward from the housing, and an aft flange projecting radially outward from the housing. The mid flange is spaced axially between the forward and aft flanges and is configured to detachably engage an inner diffuser case of the case assembly. The forward flange is configured to detachably engage a high pressure compressor and the aft flange is configured to detachably engage a high pressure turbine of the engine.