Pigmented Villonodular Synovitis (PVNS)β£What is PVNS? Other name?Benign, mono-articular proliferation of synovial tissue either in joint or in tendon sheath.Tenosynovial Giant Cell Tumorsβ£Common locations?Anterior knee is the most common site of involvement (80%)knee > hip > ankle > shoulder > elbowβ£Why is it brown in colour?Hemosederinβ£What do patients present with?Intra-articular: recurrent haemathrosis, pain, lockingβ£Spectrum of presentation?Intra-articular (Knee 80% > Hip > Shoulder > Ankle).Nodular/ localisedDiffuse = with extra-articular extensionExtra-articular (tendon sheath) = GCT of tendon sheathβ£Invx? What feature on MRI?XR cannot differentiate PVNS and SC as no calcificationsCalcificiations = synovial osteochondromatosisMRI - subchondral erosions Both T1 and T2 hypointense due to Iron depositionβ£What is the histology of PVNS?Hemosederin stained multinucleated giant cellsβ£Any common differential diagnosis?Synovial chondromatosis - (no ossification too)Lipoma Aborescens - lipoma like benign villous proliferation of synoviumβ£Can we treat this conservatively?Not recommended as it can erode into the bone in the long term and lead to early OAβ£Management of LOCALISED type?Local, Nodular β arthroscopic excisionβ£Management of DIFFUSE type?Diffuse β Open synovectomy or arthroscopicOpen - can be combination of anterior and posterior approachesβ£What is recurrence rates in Diffuse type?30%β£βΌοΈ How to reduce recurrence?External Beam Radiotherapy 30 gray can reduce to 10-20% (less popular now)Intra-articular radioisotope yttrim -90 injectionInject radioisotope 6/52 after surgery to prevent leakNot recommended in Ankle due to skin necrosis