Synovial chondromatosis is a benign nodular cartilaginous proliferation arising in the synovium of joints. The radiolographic features of this condition are variable. Rarely, it would be confused with malignancy such as chondrosarcoma, osteosarcoma or synovial sarcoma. We report a case of primary synovial chondromatosis of the posterior aspect of the proximal tibia mimicking a parosteal osteoarcoma on the radiography, which showed a homogeneously radiopaque juxtacortical mass. However, subsequent computed tomography (CT) showed multiple intra-articular masses containing chondroid mineralization, suggesting synovial chondromatosis.
Chondromatosis, Synovial ; Chondrosarcoma ; Diagnostic Imaging ; Joints ; Knee ; Osteosarcoma ; Sarcoma, Synovial ; Synovial Membrane ; Tibia

Humans ; Sarcoma, Synovial/diagnostic imaging* ; Infratemporal Fossa ; Tomography, X-Ray Computed

Adolescent ; Antigens, CD34 ; metabolism ; Bone Neoplasms ; diagnostic imaging ; metabolism ; pathology ; Chondrosarcoma, Mesenchymal ; metabolism ; pathology ; Diagnosis, Differential ; Hemangiopericytoma ; diagnostic imaging ; metabolism ; pathology ; Humans ; Male ; Platelet Endothelial Cell Adhesion Molecule-1 ; metabolism ; Sarcoma, Synovial ; metabolism ; pathology ; Tomography, X-Ray Computed ; Vimentin ; metabolism

Adamantinoma ; diagnostic imaging ; metabolism ; pathology ; surgery ; Adult ; Diagnosis, Differential ; Female ; Femur ; Follow-Up Studies ; Humans ; Humerus ; Ilium ; Keratins ; metabolism ; Male ; Middle Aged ; Mucin-1 ; metabolism ; Retrospective Studies ; Sarcoma, Ewing ; pathology ; Sarcoma, Synovial ; pathology ; Tibia ; Tomography, X-Ray Computed ; Young Adult