“…1 Although mature ossification is generally associated with a benign aetiology, sarcomas such as synovial sarcomas and primary soft-tissue chondrosarcomas, and osteosarcomas may also contain dense calcification or ossification. 6,10,[17][18][19] Internal calcification (less common than ossification) in synovial sarcomas is usually seen in the periphery. 6,10,17 These may have coexistent bone involvement and are cytologically active, and are thus readily regarded as being sarcomatous.…”