Giant cell tumour with secondary transition to aneurysmal bone cyst. .

An approximately 2.8 x 1.7 x 2 cm expansile complex cystic lesion involving the proximal part of 1st metacarpal bone extending up to the carpometacarpal subchondral region – represents giant cell tumour with secondary transition to aneurysmal bone cyst. .

The lesion demonstrates multiple small loculations containing suspicious small fluid – fluid levels , marked diffuse thinning of the cortex without obvious dehiscence. No evidence of extraosseous component.

No evidence of intra-articular extension. No evidence of abnormal flow voids