Evaluation of the hip with pigmented villonodular synovitis. A case report.

Pigmented villonodular synovitis (PVNS) is an uncommon disorder of the synovium that rarely involves the hip joint. The natural history of an untreated case of PVNS is presented herein. A young adult with a painful hip and destructive changes on plain roentgenograms requires further diagnostic evaluation. The relative value of current imaging techniques is discussed in this report. Plain roentgenograms alone often suggest the correct diagnosis of PVNS of the hip, but traditional criteria have proven to be inaccurate. Computed tomography (CT) is helpful in demonstrating the location and degree of bone loss throughout the pelvis and assists in determining the need for bone graft or prosthetic modification in preoperative planning. Experience with magnetic resonance imaging (MRI) in this disorder is limited, but no clear advantage over CT has been demonstrated thus far. Three-dimensional reconstruction has provided no useful information not already found on plain CT or MRI. For diagnostic accuracy and effective preoperative planning, evaluation should include a complete blood count, sedimentation rate, CT scan, and MRI.