Pigmented villonodular synovitis in children: a report of six cases and review of the literature.

We report six children with pigmented villonodular synovitis. They ranged in age from seven to fifteen years. In four patients, the knee was involved. One patient had involvement of the ankle, and one had diffuse involvement along a metacarpal. In five cases, the diagnosis was not suspected clinically or radiographically, and the delay in making the correct diagnosis was as long as two years. Clinical diagnosis in these five patients was usually bacterial synovitis or juvenile rheumatoid arthritis. We feel that the diagnoses of pigmented villonodular synovitis should be considered in any child with chronic joint effusion.