Axial computed tomography of the pelvis with oral and intravenous contrast material, at the level of the greater sciatic foramen, demonstrating a sinus tract extending to the right piriformis (red arrow), originating from a segment of the distal ileum (not shown). Segmental, transmural distal ileal wall thickening is also shown (blue arrows). Patient also has multiple ileocolic fistulae (not shown).