Premalignant Bone Lesions and malignant transformation

Premalignant Bone Lesions and malignant transformation

1. Premalignant Bone Lesions & Malignant Transformation Postgraduate-level Overview

2. Introduction - Premalignant bone lesions: benign conditions with risk of malignant transformation - Clinical importance: early recognition and surveillance

3. Risk Factors for Malignant Transformation - Genetic predisposition - Radiation exposure - Chronic inflammation (osteomyelitis, sinus tracts)

4. Premalignant Bone Lesions – Risk of Malignancy Premalignant Bone Lesion Malignancy Risk Common Malignant Transformation Paget’s disease of bone ~1–10% Osteosarcoma > Fibrosarcoma, Chondrosarcoma Ollier’s disease ~25% Chondrosarcoma Maffucci syndrome ~50% Chondrosarcoma, Angiosarcoma (rare) Multiple osteochondromas 5–10% Chondrosarcoma Fibrous dysplasia <1% (↑ if polyostotic/radiated) Osteosarcoma, Fibrosarcoma, Chondrosarcoma Bone infarct Rare Osteosarcoma Chronic osteomyelitis (sinus) Rare SCC of sinus tract Giant cell tumor (esp. post-RT) Rare Malignant GCT / Osteosarcoma

5. Key Notes on Specific Lesions Paget’s disease → Osteosarcoma risk (elderly, pelvis/femur common) Ollier’s / Maffucci → High risk of chondrosarcoma Multiple osteochondromas → 5–10% → chondrosarcoma Fibrous dysplasia → rare, but ↑ risk post-RT GCT (post-radiation) → secondary sarcomas

6. Clinical Pearls Surveillance & follow-up importance Imaging & biopsy in suspicious lesions Avoidance of radiotherapy in benign bone lesions (↑ malignant risk)

7. Summary – High Yield for Exams Most common malignant transformation → Chondrosarcoma Highest risk → Maffucci syndrome (~50%) Post-radiation risk → GCT, fibrous dysplasia

8. References - Abeloff’s Clinical Oncology - DeVita, Hellman, and Rosenberg’s Cancer: Principles & Practice - Campbell’s Operative Orthopaedics