Sharma DSA: Clinical MSK radiology Flashcards
Osteoporosis
-decreased cortical thickening
Osteopetrosis
-diffuse, dense bone
Osteitis deformans (paget disease of bone)
-thickening of calvarium
Osteonecrosis (avascular necrosis)
- X ray: irregular lucencies with adjacent sclerosis
- MRI: dark serpinginous necrotic bone
Ankylosing spondylititis spondylititis
-Bamboo spine
Giant cell tumor
-Soap bubble appearance
Osteochondroma
-exotosis of bone
Osteosarcoma
- “sunburst pattern”
- Codman triangle around metaphysis of long bones
Ewing sarcoma
-Onion skin around diaphysis of long bone
Type 1 vs Type 2 osteoporosis
- 1: post menopausal
- 2: >70 yrs old
What is the cell dysfunction in osteoporosis and osteopetrosis?
- porosis: blasts are the problem
- Petrosis: clasts are the problem
What enzyme mutation impairs the ability of osteoclasts to generate acidic environment?
-Carbonic Anhydrase
What gets filled in osteopetrosis?
- the bone marrow spaces
- this can lead to pancytopenia, extramedullary hematopoiesis
Pathology of Osteitis deformans (paget disease of bone)
- increased bone resorption (osteoclasts), followed by exuberant new bone formation
- the new bone is abnormal and woven with disorganized collagen
- The increased bone formation results in bone enlargement and deformity because of poor
- increased risk of developing osteogenic sarcoma
What is the marker for Paget disease of bone?
- normal Ca2+ phosphorous levels
- Serum alkaline phosphate elevated
- Urine hydroxyproline increased
What does the skull look like in paget disease?
- diploic thickening of inner and outer calvarium
- cotton wool appearance: mixed lytic and sclerotic lesions
- Frontal bone enlargement, with the appearance of the skull falling over the facial bones
What kind of pattern will we see with paget disease?
-mosaic pattern
Osteonecrosis (avascular necrosis)
- infarction of bone
- most common site is the femoral head (medial circumflex femoral artery)
- painful
Radiology for osteonecrosis
- crescent sign
- double line on T2W1
- rim sign form osteochondral fragmentation
Ankylosing spondylitis
- Arthritis w/o rheumatoid factor
- HLA-27
- spine and SI joints
- bamboo spine
- atlantoaxial subluxation
Giant Cell Tumor (osteoclastoma)
- 20-40 y/o
- locally aggressive benign tumor
- at the knee
- arise in epiphysis but may extend into metaphysis
Radiology of giant cell tumor (osteoclastoma)
- Soap bubble appearance
- multinucleated giant cells
- narrow zone of transition
- overlying cortex: thinned, expanded or deficient
Clinical course
- typically treated with curretage
- but 40% to 60% have local recurrence
- adjuvant therapy with RANKL inhibitors like denosumab has been recently added to the regimen
Osteochondroma
- males <25
- develop only in bones of endochonral origin and arise from the metaphysis near the growth plate of long tubular bones especially around the knee
- occasionally, they develop around from bones of the pelvis, scapula, and ribs
- slow growing, impinge on nerves
radiology of osteochondroma
-cartilage capped tumor that is attached to the underlying skeleton by a bony stalke
What is the best imaging modality to assess cartilage thickness and thus malignant transformation of osteochondroma?
-MRI
Osteosarcoma
- bimodal distribution
- in kids: around the knee
- in adults: they will have conditions that predispose to osteosarcoma… most commonly in the pelvic area
Radiology for osteosarcoma
- Codman triangle because cortex lifted by tumor
- sunburst appearance of bone (sharpey’s fibers
What is the method of choice for tumor staging in osteosarcoma?
-MRI
Where does osteosarcoma like to met to?
-the lungs!
Ewing Sarcoma
- malignant tumor characterized by primitive round cells without obvious differentiation
- t(11,22) causing fusion of EWS-GLI 1
- white boys <15
- diaphysis of long bones
How does Ewing sarcoma present?
- painful enlarging masses, and the site of infection is warm, tender, and swollen
- some affected individuals have systemic findings that mimic infection, including fever, elevated ESR, anemia, and leukocytosis
Radiology of Ewing sarcoma
- destructive lytic tumor… moth-eaten appearance
- periosteal rxn produces layers of reactive bone deposited in an onion-skin fashion
Clinical course of ewing sarcoma
- extremely aggressive with early mets, but responsive to chemo
- amount of chemo-induced necrosis is an important prognostic finding
