62-year-old male, chronic bone pain of distal lower limb, skin is warm to touch, especially pretibial. Progressive deformity of tibia. Previous multiple episodes of pain. X-ray shows short, horizontally running cortical tears. Autopsy specimen of a femur condyle.
- The spongiosa and fanned out “spongiosed”
compacta shows a loss of corticospongioid demarcation.
- Increased activity of osteoblasts, which are larger in number and size.
- Bone marrow fibrosis
- Mosaic pattern of the repeatedly remodelled bone substance
the mosaic pattern is pathognomonic and occurs as a consequence of the increased and irregularly running bone substance but only after repeated bouts of osteoclastic activity. The bizarre extensions of the mosaic pattern are not yet apparent.