Micrograph showing mixed uremic osteodystrophy

Bone biopsy in mixed uremic osteodystrophy which is characterized by features of both osteitis fibrosa and osteomalacia.
(Left panel) Trichrome stain reveals increased numbers of multinucleate osteoclasts (short arrow) as expected in osteitis fibrosa plus a marked increase in adjacent nonmineralized osteoid in red-brown (long arrow).
(Right panel) Tetracycline labeling demonstrates impaired mineralization as evidenced by diffuse tetracycline deposition (yellow stain, short arrow) and the absence of tetracycline at some bone forming surfaces as in the lower left quadrant (long arrow).

Histologic appearance of normal bone.
(Left panel) Goldner Masson trichrome stain shows mineralized lamellar bone in blue and adjacent nonmineralized osteoid in red-brown. Osteoid usually comprises less than 25% of bone surfaces. The cellular area between the osseous structures is the marrow space.
(Right panel) Villanueva-stained section viewed under polarized light following time-spaced tetracycline labeling. Osteoid appears orange, mineralized bone is green, and tetracycline markers appear as luminescent yellow-green bands within bone and beneath osteoid (arrow). The distinct dual bands represent active mineralized bone formation.