In Paget's disease of bone, the osteitis deformans stage is characterised by osteoclastic overactivity. The radiological sign of a 'blade of grass' or 'flame-shaped' lytic lesion advancing along the diaphysis is specifically seen in which bone?
- A Vertebral body
- B Tibia (long bones) ✓
- C Skull
- D Pelvis
Explanation
The 'blade of grass' (or 'flame-shaped') advancing radiolucency is pathognomonic of Paget's disease in long bones, particularly the tibia. It represents the osteoclastic resorption front advancing along the cortex from one end. In the skull, Paget's produces 'osteoporosis circumscripta' (large lytic lesion). In vertebrae, the 'picture frame' pattern (thickened cortex with trabecular sclerosis) is typical. The pelvic 'brim sign' (thickened iliopectineal line) is characteristic in the pelvis. The blade-of-grass lesion in a long bone combined with anterior tibial bowing is a classic NEET PG Paget's question.
Reference: Maheshwari Essential Orthopaedics, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.