A cell found in the bone marrow at the junction between the bone marrow and the bone. Active myeloma growth stimulates the osteoclast to destroy bone. This process is called resorption. Normally bone resorption is counterbalanced by the activity of osteoblasts, which create new bone. In myeloma, osteoblast activity is blocked. The combination of accelerated bone resorption and blocked new bone formation results in lytic lesions.
An osteoclast (from the Greek words for "bone" and "broken") is a type of bone cell that removes bone tissue by removing the bone's mineralized matrix. This process is known as bone resorption. Osteoclasts and osteoblasts are instrumental in controlling the amount of bone tissue.