Bone Cysts McMaster Faculty of Health 动脉瘤性骨囊肿麦克马斯特大学健康课件.pptVIP

Aneurysmal Bone Cysts(ABC’s) Dr. Ted Scriven Sept 8, 2008 ABC’s Classified as a benign boney lesion More specifically, “benign-aggressive” Benign-aggressive = marked bone destruction, soft tissue extension or pathologic fractures Etiology Specific translocation @ 17p13 Can arise de novo, or be associated with another primary: GCT, chondroblastoma, UBC, osteoblastoma, fibrous dysplasia, nonossifying fibroma, chondromyxoid fibroma, osteosarcoma Etiology Result from local circulatory abnormality: Increased venous pressure Local hemorrhage Osteolysis More bleeding Source of bleeding = capilliaries in cyst membrane Hemorrhage progresses to destructive lesion Clinical Picture Age: often 20 Gender: F M (slight) Location: metaphysis or metadiaphysis of long bones (prox humerus, distal femur, prox tibia) Occasionally iluim or lumbar vertebrae (15 – 20%) Clinical Picture Mild pain or swelling May have neuro deficits with spinal lesions Duration = weeks ? years Symptoms may worsen with pregnancy (more blood volume) Investigations Start with thorough Hx PE Xray: Radiolucent destructive cyst, expands surrounding cortex ? “Soap-Bubbles” Often eccentric, can be central or subperiosteal Investigations Bone Scan: Diffuse or peripheral tracer uptake Central area of decreased uptake Angiography: Accumulation of contrast throughout +/- hypervascularity of periphery Absence of viable afferent or efferent vessels Investigations CT Helps deliniate lesion in areas of complex boney anatomy MRI Multiloculated cavities, fluid levels, +/- associated soft tissue mass Helps to differentiate between ABC UBC DDx UBC Chondromyxoid Fibroma Chondroblastoma GCT Osteoblastoma Talengiectatic Osteosarcoma Pathology Gross: Cavitary w/ blood filled spaces Surrounded by thin layer of bone raised periosteum Pathology Micro: Hemorrhagic tissue with spaces separated by cellular stroma No endothelial lining or smooth muscle – only lining is compressed fibroblasts ALWAYS be sure to examin