<prompt> Soap bubble appearance on Xray is seen in which bone tumor -Osteogenic sarcomaGiant cell tumorMultiple myelomaChondroblastoma  <response>: Ans. is b i.e., Giant cell tumor Characteristic radiological features of few bone tumors Celery-stick appearance Enchondromas Coat-hanger appearance Osteochondroma Codman tumor and chicken-wire calcification Chondroblastoma Double density sign on radionuclide scan Osteoid osteoma Nidus and sclerotic rim Osteoid osteoma Driven snow appearance Pindborg tumor Fallen fragmentHinged fragment sign Simple unicameral bone cyst Eggshell covering of expansile cortex over surface of lesion ABC Soap bubble appearance ABC Soap bubble appearance goes into corners GCT Osteoclastoma Floating tooth sign Eosinophilic granuloma, adamantinoma Onion skin onion peel appearance Ewing sarcoma Skip lesions Osteosarcoma, Ewings sarcoma SunraySunburst appearance Osteosarcoma String sign to differentiate from myositis ossificans Parosteal osteosarcoma Popcornmottled calcification Chondrosarcoma Shepherds crook deformity Fibrous dysplasia Codmans triangle Osteosarcoma, Ewing sarcoma Winking owl sign Metastasis to pedicles of vertebra Corduroyaccordion vertebravertical striations Vertebral hemangioma Polka dot sign on CT Vertebral hemangioma Geographical skull Eosinophilic granuloma Hole-within-a-hole lesion Eosinophilic granuloma 