A patient presented with pain in his ankle. X-ray was done which shows osteolytic lesion with sclerotic rim. HPE findings are attached. What is your diagnosis?

Ans. C. Hemophilic pseudotumorX-ray is useful in diagnosing intraosseous pseudotumors. They appear as well-defined, unilocular or multiloculated, lytic, expansile lesions of variable size. In this case, it can involve metaphysis, diaphysis, and epiphysis of long bones.Other findings include endosteal scalloping, perilesional sclerosis, cortical thinning or thickening, trabeculations, and septations. Pathological fractures can also be present.