Ganglion cyst of the anterior cruciate ligament: a case report.

A ganglion is a cystic swelling that usually arises close to tendons or joints. Its occurrence inside a joint is rare, and its diagnosis is usually incidental during magnetic resonance imaging or arthroscopy. It may be painful or asymptomatic. Some patients may have a trauma history. Ganglia may mimic intra-articular lesions like tears of the anterior cruciate ligament or meniscus. Magnetic resonance imaging is the investigation of choice for diagnosis. Ganglia commonly arise from the anterior cruciate ligament, but can also arise from other structures such as the posterior cruciate ligament or meniscus. Ganglia are typically treated by arthroscopic excision and debridement. We report a case of ganglion cyst of the anterior cruciate ligament in a 16-year-old man.