Microscopic examination of pagetic bone shows thickened trabeculae composed of lamellar bone intersected by numerous irregular, haphazardly placed cement lines. This appearance corresponds to which classical description?
- A Fish-scale pattern of woven bone with osteoid seams
- B Mosaic pattern of lamellar bone, like a jigsaw puzzle ✓
- C Chinese letter pattern of fibrous dysplasia
- D Onion-skin layering of reactive periosteal new bone
Correct answer: B. Mosaic pattern of lamellar bone, like a jigsaw puzzle
Explanation
Repeated waves of osteoclastic resorption followed by disordered osteoblastic repair create lamellar bone criss-crossed by prominent cement lines, giving the diagnostic mosaic or jigsaw puzzle pattern. This pattern persists even in the sclerotic burnout phase. The Chinese letter pattern belongs to fibrous dysplasia, onion-skin layering to Ewing sarcoma or chronic osteomyelitis, and fish-scale osteoid seams to osteomalacia, where unmineralised osteoid surrounds trabeculae.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.