Young Skeleton with pain after fall shows exophytic opacity outwards from the metaphyseal location of humerus with undisplaced fractures in the vicinity with almost 2 Humeral heads appearance suggesting exostosis with suspicion for secondary chondrosarcoma of cartilage cap. MRI is needed for further evaluation.
Teaching points by Dr MGK Murthy, Dr Sumer Sethi.
· Defined as developmental dysplasia of peripheral growth plate which forms cartilage cap projection of bone near metaphysis of long bones. Peripheral chondroblast grows outwards acting as ectopic growth plate , stopping at maturity
· Most common benign bone tumor. Any bone forming in cartilage can get involved
· X ray hallmark is blending of tumor in to the underlying metaphysis along with calcification of cap elements
· Only 1% solitary ones can turn secondary chondrosarcoma at the cap , with 10% in multiple variety
· Cartilage cap measuring >1cm in adults and 2-3 cms in children on MRI along with sudden increase in bone scan uptake in adults is of concern
· Other complications include bursal formation