Polyarticular extension of pigmented villonodular synovitis to contiguous joints via pigmented villonodular tenosynovitis.

Pigmented villonodular synovitis is an uncommon benign neoplastic process that affects synovial-lined joints, bursae and tendon sheaths. We describe polyarticular extension of pigmented villonodular synovitis across joints secondary to pigmented villonodular tenosynovitis. Given that treatment is required to prevent progressive destruction of the involved joint, tendon or bursa, radiologists must be vigilant for diffuse polyarticular or extrasynovial involvement to optimize patient care and initiate appropriate therapy.