Abstract
We treated a case of localized nodular synovitis (LNS) in the knee joint under arthroscopy. This case was 30 year old male, who visited our hospital because of pain and mass of right knee joint. We performed arthroscopy and pedunculated tumor was found at medial synovia. It was resected completely and it was diagnosed as LNS.
Previously LNS was regarded as a part of pigmented villonodular synovitis (PVS). However it should be treated as another entire of disease as it's clinical cause in differ from the PVS.