Clinical features: An executive in an IT firm, presented with locking of knee, after getting up in morning. After walking for while, he is fine. He has no previous history of trauma, or any sports related injury (He doesn't play any sport in fact).
Radiological features: A synovial nodular (loose body) mass lesion is seen, with heterogenous signal characteristics. Foci of hypointensity on T1W and T2W images, with marked hypointensity on GRE images are seen within the lesion.
Provisional diagnosis: Possibility of pigmented villonodular synovitis (PVNS) is considered. Differential diagnosis include 'cyclops lesion', intra-articular chronic hematoma. However, in view of lack of trauma related history, and intact ligaments (ACL, Menisci, PCL), PVNS merits primary consideration.
Patient is not ready for any intervention, and sustaining similar symptoms since the study done in June 2011. Pathological diagnosis is unavailable.