This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Skeletal System, Subject name: Radiology
[{'content': 'Expansile lytic lesion with fluid-fluid levels involing the proximal metaphysis of fibula in an early adolescent female is typical of? \nSelect and explain. \nA. Giant cell tumor, B. Aneurysmal bone cyst, C. Hemangioma, D. Fibrous dysplasia', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. b (Aneurysmal bone cyst) (Ref: Bailey 26th/533; Grainger Diagnostic radiology 4th ed. 2463)Aneurysmal bone cyst is a benign cystic lesion of bone consisting of blood-filled spaces separated by fibrous septa. The lesion is much more aggressive than a simple bone cyst and often presents with pain and swelling. Plain x-rays show commonly aggressive features with eccentric expansion of the cortex and an open physis. MRI. often show multiple fluid levels.Few bone tumors AgeCommon site featuresRadiological SignSpecificAdditional commentsGCT (Osteoclastoma)20-40 yrs# Epiphysis# Around "knee# Lytic# Expansile# Eccentric# Subarticular" Soap-bubble" appearance# Benign bone tumor# Conservative surgery like curettage is associated with 40-60% recurrence rate.# Up to 4% metastasize to lung.ABC# peak age 16 years (range 10-30 years);# F>.M# Metaphysis# Diatal end of humerus is most common site# Purely lytic eccentric radiolucency# Expansile ballooning lesion with/ without Soap-bubble pattern# Rapid progression within 6 weeks to 3 months# Sclerotic inner portion# Tumor respects epiphyseal plate.Fluid-fluid/ Fluid-blood levels20--30% recurrence rateHEMAN- GIOMA# 4th--5th decade;# M:F = 2:1Vertebra (28% of all skeletal hemangiomas) in lower thoracic/ upper lumbar spine.Vertebra with vertical striations i.e. Corduroy/ Accordion vertebra"Polka-dot" appearance on CT# Mostly cavernous;# In spine Percutaneous Vertebroplasty is a good Rx option.FD# Usually early adolescence- M=F# Usually diaphyseal.# Ribs, femur, tibia, jawbones, calvaria, and humerus are most commonly affected, in descending order.# Well-defined mixed-density lesion"Ground-glass" appearance or smoky matrix# Benign tumor# Usually asymptomatic# Monostotic form does not evolve into polyostotic form.# Polyostotic form accounts for 27% of cases, Monostotic form 70% cases and 3% are seen as a part of McCune-Albright syndrome.# In polyostotic form rarely transformation into osteosarcoma/ malignant fibrous histiocytom may occur.', 'role': 'assistant'}]