Abstract Background Osteitis fibrosa cystica is a rare. benign and osteolytic lesion attributed to hyperparathyroidism. The high level of parathyroid hormone cause rapid bone loss. Case presentation The patient is a 50-year-old male complaining of severe and persistent pain in the right knee joint. https://www.roneverhart.com/Echo-Fix-EF-P2-Spring-Reverb-Pedal-p32083/