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What is An 11year old boy presented with the complaints of pain in the right arm near the shoulder. X-ray examination revealed an expansile lytic lesion in the upper third of humerus. The most likely diagnosis is - and explain in detail?
Two most important differential diagnosis of expansile lytic lesion in proximal humerus and proximal femur in children are : -


Simple bone cyst (unicameral bone cyst)
Aneurysmal bone cyst


Among these two, only unicameral bone cyst is there in options. Therefore, no further discussion is required.