Long-Term Follow-up Results of Advanced or Multiply Recurrent Pigmented Villonodular Synovitis/Tenosynovial Giant Cell Tumor Following External Beam Radiation Therapy

Abstract

Pigmented Villonodular Synovitis (PVNS) and Tenosynovial Giant Cell Tumor (TGCT) are rare proliferative disorders of the synovial membrane that represent two manifestations of the same disease spectrum. While TGCT presents with focal lesions, PVNS exhibits greater clinical aggression partly due to its diffuse form affecting the entire synovium. Primary treatment involves extensive surgical resection of the involved hypertrophic synovium to achieve local control. Unfortunately, complete removal of all lesions is often difficult to achieve, leading to refractory and multiply recurrent disease for a disorder considered essentially benign. Such high-risk cases may lead to local destruction and severe symptoms including joint pain, swelling, hemorrhagic effusion, and erythema. In this report, we reviewed our experience treating advanced and recurrent PVNS with postoperative external beam radiation therapy. We identified twenty-nine patients diagnosed with PVNS and subsequently treated with radiation therapy between 2003-2017. Each case was retrospectively reviewed for patient demographics, radiation treatment parameters, surgical treatments, complications, and outcomes. All patients had diagnostic imaging and pathological review at presentation. With a median follow-up of 26.91 months (range, 2.17-191.69 months), 24 patients (83%) achieved initial local control following radiation therapy. Ultimate local control was achieved in 27 patients (93%). The most common location of disease was the knee joint with 20 cases (69%), followed by the ankle with 5 (17%), the hand with 3 (10%), and the hips with 1 (4%). Six sites (21%) were primary presentations and 23 sites (79%) were recurrent, with an average of 2.78 surgical interventions before radiation therapy. Following cytoreductive surgery, 18/27 sites (67%) had suspected or proven residual PVNS. The mean dose of radiation delivered was 34.7 Gy (range, 7-36 Gy). Twenty-five sites (86%) had post-radiation therapy imaging. In the assessment of PVNS-related function, 26 joints (90%) were scored as excellent or good function, 2 joints (7%) as fair, and 1 joint as poor (3%). The patient with poor function underwent two further surgical interventions that was complicated by wound dehiscence and infection, which ultimately led to above the knee amputation. Radiation therapy was well tolerated with no Grade 3/4 complications. For patients presenting with extensive or refractory PVNS, postoperative external beam radiation therapy provided excellent local control and maintained good functional status. Adjuvant radiation in moderate doses eschewed treatment-related complications and thus should be offered following maximal cytoreduction to prevent disease recurrence.