Teenager 12 years-old with complaints of pain in the knee, an injury denies.
At US at the side of pain backwards to the quadriceps tendon there is a little amount of fluid, in the contralateral side backwards to the patella there is a little amount of fluid and anterior to the lateral meniscus visualized anechoic lesion with a septum (meniscal cyst? meniscus tear? hematoma?)