Intracapsular (osteo-)chondroma of the knee is a rare benign tumor of cartilaginous origin due to extrasynovial metaplasia, usually located within the infrapatellar fat pad.

The main differential diagnoses include:

• localized tenosynovial giant cell tumor (also known as intraarticular giant cell tumor of the tendon sheath)

• calcified synovial sarcomas

• calcifying bursitis

• primary synovial chondromatosis

• periosteal chondromas