Page 691 - TNFlipTest

Toronto Notes 2019 Musculoskeletal System
• expansile
■ aneurysmal bone cyst, giant cell tumour, enchondromas, brown tumours, metastases (especially
renal and thyroid), plasmacytoma • matrixmineralization
■ chondroid (popcorn calcification) or osseous
• margin/zoneoftransition:areabetweenlesionandnormalbone
• cortex: intact, disturbed
• periostealreaction:onion-skinning,sunburst,Codman’striangle,periostealneocortex • softtissuemass
Medical Imaging MI23
Margination of lesions
Punched out
Thin rim of sclerosis
Thick rim of sclerosis
Patterns of cortical disturbance
Expansile
Endosteal scalloping
Invisible margin
Saucerization
Patterns of medullary destruction
Permeative
Moth-eaten
Periosteal new bone formation
Onion-skin layered
Codman's Triangle
Hair-on-end spiculated
Sunburst divergent
Solid undulating
Benign Lesions which may have Aggressive Features
• Osteomyelitis
• Osteoblastoma
• Aneurysmal bone cyst
• Langerhans cell histiocytosis • Myositis ossificans
Periosteal Reaction
• “Onion skinning” = Ewing’s sarcoma
• “Sunburst”, “hair on end” = osteosarcoma • “Codman’s triangle” = osteosarcoma,
Ewing’s sarcoma, subperiosteal abscess
Figure 39. Radiographic appearance of bone remodelling and destruction processes Table 18. Characteristics of Benign and Malignant Bone Lesions
Benign
Thin sclerotic margin/sharp delineation of lesion Overlying cortex intact
No or simple periosteal reaction
No invasion of surrounding soft tissue
Metastatic Bone Tumours
Malignant
Poor delineation of lesion – wide zone of transition Loss of overlying cortex/bony destruction Periosteal reaction
Invasion of surrounding soft tissue
• allmalignancieshavepotentialtometastasizetobone
• metastasesare20-30xmorecommonthanprimarybonetumours
• metastasiscancausealyticorascleroticreactionwhenseedingtobone
• whenaprimarymalignancyisfirstdetected,abonescanisoftenpartoftheinitialworkup • maypresentwithpathologicalfracturesorpain
• biopsyordeterminationofprimaryistheonlywaytoconfirmthediagnosis
• mostcommonmetastaticbonetumours:breast,prostate,lung,seeOrthopedics,OR46
Lytic = decreased density Sclerotic = increased density
“KLM flies to periphery” Kidney
Lung Melanoma
Table 19. Characteristic Bone Metastases of Common Cancers
Lytic Sclerotic
Breast Prostate Lung Breast Thyroid Lymphoma Kidney Lung Multiple myeloma Bowel
Medulloblastoma Treated tumours
Expansile
Thyroid Renal
Peripheral
Kidney
Lung
Melanoma
(KLM: flies to the periphery)
Infection
Osteomyelitis
• MRIistheimagingmodalityofchoicefordemonstratingbone,bonemarrow,andsofttissue abnormalities
• 99mTc,followedby111In-labeledwhitecellscanorgalliumradioisotopescan
• plainfilmchangesvisible8-10dafterprocesshasbegun
■ soft tissue swelling
■ local periosteal reaction
■ pockets of air (from anaerobes) may be seen in the tissues, may also suggest necrotizing fasciitis ■ mottled and nonhomogeneous with a classic “moth-eaten” appearance
■ endosteal scalloping
■ cortical destruction
■ peripheral sclerosis (late sign)
© Patrick Cervini 2002