The quadriceps tendon cyst: an uncommon cause of chronic anterior knee pain.

The causes of knee pain are manifold. One of the uncommon causes of chronic anterior knee pain are cysts and ganglia. Magnetic resonance imaging not only reveals the intra-articular pathology but also accurately depicts such cystic structures about the knee. As part of this case report, a cyst of the lateral border of the quadriceps tendon is presented as a cause of such discomfort. Although cystic lesions around the knee are a common clinical problem, the described location is rare. After surgical revision of the lateral border of the quadriceps tendon and excision of the cyst, the patient was found to be asymptomatic.