<prompt> Polka dot appearance on CT scan is seen in which of the following?Ewings sarcomaOsteosarcomaVertebral hemangiomaEosinophilic granuloma  <response>: Ans. is c i.e., Vertebral hemangioma Characteristic radiological features of few bone tumorso Celery-stick appearanceEnchondromaso Coat-hanger appearanceOsteochondromao Codman tumor and chicken-wire calcificationChondroblastomao Double density sign on radionuclide scanOsteoid osteomao Nidus and sclerotic rimOstoid osteomao Driven snow appearancePindborg tumoro Fallen fragmentHinged fragment signSimple unicameral bone cysto Eggshell covering of expansile cortex over surface of lesionABCo Soap bubble appearanceABCo Soap bubble appearance goes into comersGCT Osteoclastomao Floating tooth signEosinophilic granuloma, adamantinomao Onion skin onion peel appearanceEwing sarcomao Skip lesionsOsteosarcoma, Ewings sarcomao SunravSunburst appearanceOsteosarcomao String sign to differentiate from myositis ossificansParosteal osteosarcomao Popcommottled calcificationChondrosarcomao Shepherds crook deformityFibrous dysplasiao Codmans triangleOsteosarcoma, Ewing sarcomao Winking owl signMetastasis to pedicles of vertebrao Corduroyaccordian vertebravertical striationsVertebra hemangiomao Polka dot sign on CTVertebral hemangiomao Geographical skullEosinophilic granulomao Hole-within-a-hole lesionEosinophilic granuloma 