"Sunray appearance" on x-rays is suggestive of :

Osteosarcoma - New bone is laid down along the blood vessels within the tumor growing centrifugally giving rise to a 'Sun -ray appearance' on x -ray. Chondrosarcoma- "Speckled" calcification on x-ray Ewings sarcoma - Second most common malignant. Classic x-ray appearance is the "onion skin"