“…Two types of cystic lesions of the ACL can be distinguished by MRI: purely cystic lesions, which include mucoid cysts; and infiltrative lesions, also known as hypertrophy, mucoid degeneration, or infiltrative pseudocyst of the ACL [9] . Mucoid cysts of the knee are neo-formed cystic lesions consisting of one or multiple cavities containing highly viscous mucoid fluid and surrounded by a pauci-cellular fibro-conjunctive wall [ 10 , 11 ].…”