TIBIA - Osteogenic sarcoma

The upper end of the tibia is occupied and expanded by tumour showing a rather whorled appearance; although the tumour appears circumscribed, it is in fact extending through the periosteum on the front of the tibia and through the articular cartilage into the joint space superiorly. There is an irregular cavity present in the centre which represents the end result of necrosis. Histologically the lesion is poorly differentiated.