Pigmented villonodular synovitis: an uncommon presentation of anterior hip pain.

Pigmented villonodular synovitis (PVNS) is a rare, benign, idiopathic proliferative disorder of the synovium that results in villous or nodular formation in joints, tendon sheaths, and bursae. The disease can be localized or diffuse. Its estimated prevalence is 1.8 cases per million in the United States. Large joints, such as the knee and hip, are commonly affected. Patients with this condition typically present with symptoms of mild discomfort and associated stiffness of the involved joint; however, the spectrum of presentations is broad. We present a case of an otherwise healthy 40-yr-old man who presented for evaluation of stiffness and pain in the anterior hip. His initial presentation, work-up, and course will be discussed, along with a brief review of the literature.