Fig. 4

Pseudotumor formation after revision MoP Total hip arthroplasty. a Anteroposterior radiograph showing extensive soft tissue mass around the right hip prosthesis and a mass in pelvis. b A transaxial view of the CT showed extensive right hip high density shadow and a high density mass in pelvis. c MRI T2image showed significant artifact in the region of the right hip MoM prosthesis. Surrounding the prosthesis was extensive soft tissue and muscle edema affecting the gluteus muscles, piriformis, rectus femoris, obturator externus, pectineus, and the adductor bundle. d ^99mTc-MDP bone scintigraphy showed a photopenic area in the region of the right hip prosthesis that appears to extend into the surrounding soft tissues