<prompt> Soap bubble appearance on distal end of radius is diagnostic of -OsteoblastomaOsteoclastomaOsteosarcomaEwings sarcoma  <response>: Ans. is b i.e., Osteoclastoma Characteristic radiological features of few bone tumorso Celery-stick appearance - Enchondromaso Coat-hanger appearance - Osteochondromao Codman tumor and chicken-wire calcification - Chondroblastomao Double density sign on radionuclide scan - Osteoid osteomao Nidus and sclerotic rim - Ostoid osteomao Driven snow appearance - Pindborg tumoro Fallen fragmentHinged fragment sign - Simple unicameral bone cysto Eggshell covering of expansile cortex over surface of lesion - ABCo Soap bubble appearance - ABCo Soap bubble appearance goes into corners - GCT Osteoclastomao Floating tooth sign - Eosinophilic granuloma, adamantinomao Onion skin onion peel appearance - Ewing sarcomao Skip lesions - Osteosarcoma, Ewings sarcomao SunraySunburst appearance - Osteosarcomao String sign to differentiate from myositis ossificans - Parosteal osteosarcomao Popcommottled calcification - Chondrosarcomao Shepherds crook deformity - Fibrous dysplasiao Codmans triangle - Osteosarcoma, Ewing sarcomao Winking owl sign - Metastasis to pedicles of vertebrao Corduroyaccordian vertebravertical striations - Vertebral hemangiomao Polka dot sign on CT - Vertebral hemangiomao Geographical skull - Eosinophilic granulomao Hole-within-a-hole lesion - Eosinophilic granuloma 