Surgical Hip Dislocation for a Diagnostic Dilemma: Differentiating Synovial Chondromatosis and Pigmented Villonodular Synovitis.

Pigmented villonodular synovitis (PVNS) and synovial chondromatosis (SC) of the hip are rare synovial diseases that can induce joint destruction without early diagnosis and treatment. The extent of surgical excision is critical given the high rates of recurrence. In the presented case, a 19-year-old female was referred to our institution with progressive left hip pain and radiologic evidence of an intra-articular mass that was consistent with PVNS versus SC. Her medical history was notable for a prior excision of a fibrous lesion at an outside hospital at age 13 with persistent pain. The patient underwent a surgical hip dislocation approach to obtain near-complete visualization of the femoroacetabular joint, ensuring complete evaluation and excision. The tumor was intraoperatively diagnosed as SC and excised accordingly, during an uneventful operation. Pathology confirmed the diagnosis. The essential diagnostic and surgical steps for the management of this pelvic tumor diagnostic dilemma are described. Level of Evidence: V.