Diffuse pigmented villonodular synovitis is a rare proliferative disorder of synovial membranes with invasive and expansive growth patterns. Radical synovectomy is regarded as the treatment of choice. However, because of the high recurrence rates, additive treatment might be useful. Radiotherapy (RT) has been evaluated with positive results, but the optimal treatment schedules are vague. We have reviewed our experience with postoperative RT in cases of suspected or proven residual disease. Between December 1996 and January 2006, 7 diffuse pigmented villonodular synovitis patients underwent RT at our institution. The most common location was the knee joint (5 patients). All patients underwent radical surgery and were treated subsequently with 6-MV photon RT. The total doses applied were 30–50 Gy, depending on the resection status and estimated risk of relapse. For analysis, we retrospectively reviewed all patients in April 2006.

The mean follow-up time was 29 months (range, 3–112 months). RT had no acute adverse effects. At the assessment, no evidence was found of recurrent or persisting disease in any patient. Of the 7 patients, 6 reported asymptomatic limb function and excellent quality of life; 1 patient had persistent restriction of joint movement after repeated surgery. No radiotherapeutic late effects were seen. The results of our series have confirmed the efficacy and safety of postoperative RT for diffuse pigmented villonodular synovitis. Hence, this treatment should be considered for patients with suspected or proven residual disease.

Postoperative radiation therapy to high-risk pigmented villonodular synovitis is an effective treatment for local tumor control without severe complication. Pigmented villonodular synovitis (PVNS) is an uncommon proliferative disorder, and appears pathologically thickened, reddish-brown synovium with numerous villous projections. PVNS is classified into localized (LPVNS) and diffuse type (DPVNS). Incompletely resected LPVNS or DPVNS has relatively high local recurrence rate after surgery, although the optimal treatment is arthroscopic or open synovectomy. This study observed the local recurrence rate and treatment-related complication after postoperative radiation therapy in patients with high-risk, incompletely resected PVNS

Median follow-up time was 24 months, and its range was 13–64 months. Four (18.2%) patients showed local recurrences in radiation field. Time to recurrence was 1 year in 2 patients, and 43, 59 months in the other 2 patients. Two patients received salvage operation or re-radiation therapy. Among 18 patients without local recurrence, fifteen (83.3%) patients had good joint function without pain after treatment, one patient had mild stiffness in irradiated knee joint, and the other two patients had mild pain. No severe complication was observed in all patients.

Postoperative radiation therapy to high-risk pigmented villonodular synovitis is an effective treatment for local tumor control without severe complication

Sustained Remission Following Radiation Treatment for High-Risk Pigmented Villonodular Synovitis
B. O’Sullivan, A. Griffin, J. Wunder, P. Marks, C. Catton, P. Ferguson, P. Chung, R. Kandel, L. White, R. Bell
International Journal of Radiation Oncology * Biology * Physics 1 October 2005 (Vol. 63, Page S50)

Purpose/Objective: Pigmented villonodular synovitis (PVNS) is a rare proliferative process originating from synovial membranes. Usually benign, it may be destructive, resulting in major symptoms and loss of function leading to amputation rarely. There is a paucity of outcome data following radiotherapy in high risk cases. Our purpose was to update a prior experience with extended follow-up and almost three times greater accrual of cases at high risk for recurrence with functional loss including instances where amputation was the sole alternative for symptomatic disease.

Materials/Methods: The records of all patients (41 cases) who received radiotherapy for PVNS between 1972 and 2003 were reviewed retrospectively and, since 1986, prospectively. Eligibility included at least one year of follow-up following radiotherapy. Local control was defined as absence of clinical or imaging evidence of disease following treatment in either patients without overt disease at the time of radiotherapy, or in patients with stable disease on serial cross-sectional imaging of gross disease for at least one year following treatment.

Results: All cases had pathologic confirmation of diagnosis at our center. 18 had primary and 23 recurrent disease (with a mean of 2 prior surgical procedures). 36 had origin from a joint (most commonly the knee in 37%) and 5 arose in periarticular tendon sheath. All but 1 had both intra- and extraarticular disease and, without exception, the poorer prognosis diffuse subtype of the disease. The majority had one or more additional risk factors including skin, bone, tendon, neurovascular, or muscle group extension and 17 of these lesion exceeded 10 cm in maximum dimension. 21 had gross residual disease at the time of radiotherapy. The mean radiotherapy dose was 38 Gy (range 28 Gy to 50 Gy), the majority receiving 35 Gy in 14 fractions. One patient had the malignant variant of PVNS and is the only patient with clear resection margins consistent with oncologic principles for malignant sarcomas. With a mean follow-up time of 77 months (range 13–337 months), only one patient has shown active disease by the criteria described. Two additional cases (both tendon sheath lesions of the wrist/hand) underwent subsequent biopsies of a palpable asymptomatic stable lesion (<1 cm in size). In one this took place 9 years following radiotherapy and he remained without treatment or progression 17 years later; the second had a biopsy 16 years following treatment, had no additional therapy and was well without progression 3 years later. No patient required amputation, and none had evidence of serious radiotherapy complications. Only one patient has developed a second malignancy, specifically a brain tumor but the site of PVNS was the ankle.