1. GCT – CASE REVIEW 27 YR OLD MALE WITH SWELLING LOWER END OF TIBIA CT RT ANKLE : Eccentric expansilelytic lesion in lower end of tibia posteromedially with cortical breech and soft tissue extension ? mitotic lesion ( GCT / ABC). FNAC : Giant cell tumor of bone ( tibia lower end). MERCURY IMAGING INSTITUTE SCO 172-173 SEC 9C CHANDIGARH MERCURY IMAGING CENTRE SCO 16-17 SEC 20D CHANDIGARH

2. LOBULATED MASS WITH CORE NECROSIS , DEGENERATION SUBARTICULAR LOCATION

3. CYSTIC INTRASUBSTANCE CHANGE PSEUDOCAPSULE / OSSEOUS SCLEROSIS

4. EXPANSILE , ECCENTERIC SUBARTICULAR ,LOBULATED LESION RELATIVE SPARING OF JOINT IS APPRECIATED

5. TIBILAIS POSTERIOR TENDON

6. TIBIALIS POSTERIOR TENDON

7. GCT OSTEOCLASTOMA OSTEOBLASTOCLASTOMA MYELOID SARCOMA TUMOR OF MYELOPLAXUS FEATURES TO REMEMBER EccentericExpansilelytic lesion with narrow zone of transition Subarticular ( mature skeleton) Metaphyseal ( immature skeleton) Open epiphyseal plate acts as barrier to tumor growth

8. LESSONS LEARNT Hypointense border around the lesion is either osseous sclerosis / pseudocapsule. Core necrosis/ cysts/ degeneration – supports GCT as possibility ( Intratumoral ABC components) Tibia lower end is involved in 2 to 5 percent of cases. Soft tissue extension is more often than joint involvement. Joint involvement is rare in GCT ( appreciated more often in sacral joint). Narrow zone of transition appreciated between the lesion and normal region.