Tuberculosis of the hip as the presenting sign of HIV and simulating pigmented villonodular synovitis.

A 36-year old man, with no prior known exposure to human immunodeficiency virus (HIV) or tuberculosis, presented with monoarticular pain and a decreased range of motion in his left hip. Radiography and magnetic resonance imaging revealed bony erosive lesions, juxta-articular cysts, a large effusion, and juxta-articular edema. The initial clinical and radiographic diagnosis was pigmented villonodular synovitis (PVNS) of the left hip. However, what was initially felt to be a chronic proliferative inflammatory process was later determined to be tuberculous arthritis. This case emphasizes the importance of including tuberculous arthritis in the differential diagnosis of patients with monoarticular destructive joint disease radiologically suggestive of PVNS.