Histology Course S IX 2 Department of Pathology, University of Zurich Histology Course

S IX 2 Paget's disease of bone HE further information (German) on HiPaKu
  ICD-10: M88.8

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.