Localized pigmented villonodular synovitis of the patellar fat pad: a report of two cases.

Pigmented villonodular synovitis (PVNS) of the knee is a well-recognized entity. We report on two cases of localized PVNS that involved the patellar fat pad, an area of involvement not previously reported. Diagnostic and therapeutic arthroscopies were performed, and typical findings of localized PVNS were found. Complete resection of the lesions were performed arthroscopically. At short-term follow-up, all symptoms had resolved. Arthroscopy can be used as an effective diagnostic tool for identification of intraarticular PVNS of the knee. In the case of localized involvement, it also can be considered as definitive treatment.