Bone – Increased Osteoid

Comment: An increase in the osteoid (previously called osteomalacia) is characterized by an increase in the surface area of bone by the accumulation of osteoid (Figure 1 and Figure 2). There may be widened seams along existing surfaces of bone. Defective mineralization results in an accumulation of homogeneous, unmineralized osteoid. Increased osteoid has been induced in rats by various compounds that inhibit mineralization of osteoid, including bisphosphonates, aluminum, cadmium, phosphorus deficiency, and vitamin D toxicity. It may also be observed as new bone is rapidly being formed; increased osteoid secondary to rapid new bone formation should be differentiated from a primary defect in mineralization or inhibition of osteoclastic bone resorption.