Postoperative low-dose external radiotherapy for diffuse pigmented villonodular synovitis (PVNS) of the knee: A case report and literature review

Background: pigmented villonodular synovitis (pvns) is a rare benign proliferative disease of the synovium which most commonly affects the knee. it is regarded as a benign disease, but has a local invasion. postoperative adjuvant radiotherapy is very necessary for pvns, but there is no consensus on the total dose of radiotherapy. case presentation: a 22-year-old young male with diffuse pvns of right knee was referred to our hospital with ongoing right knee swelling and limitation of motion of the knee. preoperative magnetic resonance imaging (mri) showed synovium of the joint was obviously thickened with multiple nodular low signals of long t1 and short t2 which is the typical characteristic of pvns. the patient was treated with arthroscopic synovectomy combined with adjuvant postoperative low-dose external radiotherapy (20 gy). conclusions: based on related literature about radiotherapy of pvns, arthroscopic synovectomy combined with postoperative low-dose external radiotherapy is an ideal treatment and prevents the recurrence for pvns of the knee.