[Differential diagnosis of lateral cystic lesions in the knee joint].

Soft tissues detected on the lateral side of the knee joint may have differential diagnostic difficulties. Although most of these are benign, mostly cystic in appearance, they may raise the clinical suspicion of tumors due to their increased growth. The authors describe two rare soft tissue changes in three patients. They review the diagnostic procedures most commonly used in daily care, present surgical options, and discuss the literature of the subject.