Shimamura Y et al. - This is a case reoprt of a 50-year-old male presented with a large mass involving the left third rib following more than 30 years of a slow growing asymptomatic swelling in the chest wall. Computerised tomography (CT) scan showed a mass 7 × 10 cm expanding the left third rib and having a sclerotic outer margin which showed discontinuity and raising the possibility of malignancy arising in longstanding fibrous dysplasia (FD).