Synovial chondromatosis of Hoffa’s body is very uncommon. We report a 18-year-old female patient with synovial chondromatosis and a calcified mass inside the Hoffa’s body who presented with mechanical impairment of the knee and pain in its anterior aspect. The bony mass in the Hoffa’s body was evident on the X-ray and MRI exploration showed synovial affectation. During the arthroscopy, all pathological synovial was removed and the bony mass was extirpated through a mini-arthrotomy. Diagnosis of a giant synovial osteochondromatosis was confirmed by histology and malignancy was ruled out. Two years after surgery the patient was asymptomatic and motion range was complete.