An attachment structure for a gas turbine engine includes a frame that has a first annular case. A second annular case extends around the frame. The first annular case and the second annular case include a plurality of interlocks. Each of the interlocks includes a first member mounted on one of the first annular case or the second annular case and a corresponding second member mounted on the other of the first annular case or the second case. The first member is received in the second member such that the plurality of interlocks restricts relative circumferential and axial movement between the first annular case and the second annular case.