Pseudotumor presenting as a pelvic mass: a complication of eccentric wear of a metal on polyethylene hip arthroplasty.

The term pseudotumor was coined by Pandit et al (J Bone Joint Surg Br. 2008; 90:847) to describe the features of a soft tissue mass, which is neither infective nor malignant, that is found in association with hip arthroplasty. Most previously reported cases have been associated with a metal-on-metal articulation, with the largest series occurring after hip resurfacing. The author describes a patient who developed a pseudotumor secondary to particulate disease arising after polyethylene liner wear that led to a metal-on-metal articulation in conventional hip arthroplasty.