Para-articular osteochondroma, a benign osteoarticular tumor which develops near joints, is, unlike classical osteochondroma, extremely rare. We present the case of a 59-year-old woman who developed a calcified mass in the infrapatellar region. The differential diagnosis between chondrosarcoma, synovial chondromatosis, and para-aticular osteochondroma was only possible after resection and pathology examination of the surgical specimen. 

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