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Radiology Of Agressive And Nonagressive Bone Lesions

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sihirlifil's version from 2017-09-02 14:10

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Question Answer
Guidelines to interpret benign and aggressive lesions (6)Lesion location
Distribution of bone destruction
Zone of transition
Periosteal reaction / cortical reaction
New bone production
Rate of progression (need sequence of radiographs)
Normal, physiological changes in bone density (3)Aging (resoprtive)
Disuse (resorptive)
Athletic activity (productive, remodeling)
Abnormal, pathological changes in bone density (2)Lytic (osteoclastic)
Sclerotic (osteoblastic)
___% of mineral content must be lost for bone loss to be detected radiographically30-60%
Possible causes for generalized pattern of bone tissue destruction:Serum calcium levels (& Vit D, PTH), hyperparathyroidism, nutritional disease, disuse atrophy
Possible causes for localized pattern of bone tissue destruction:Bone tumor, infection (e.g. bacterial osteomyelitis at site of insult)
Destruction indicates intact blood supply
Indicators for metabolic diseaseAbnormal serum calcium levels
Abnormal renal parameters (renal 2ry PTHism)
Hyperadrenocorticism
What does a skull radiograph of a dog with hyperPTH look like?"Floating teeth," frontal sinus very radiolucent (decreased opacity), porous cortex
Osteomalacia = Bone never properly mineralized
What may occur as a result of generalized osteopenia?Pathological fractures from weakened bone
How can nutritional parathyroidism be resolved?Diet change. Malformations may persist if pathological fractures
What is the pattern for disuse atrophy?Generalized, usually affecting one limb/region
Radiographic findings for disurse atrophyThin, porous cortices
Reduced bone opacity
Examples of localized bone destructionBone cyst (lack of bone, rather than destruction)
Bone tumor
Bone infection
How long does it take to recognize localized lesions radiographically after insult?7-10 days
13 year old collie w/ localized monostotic lesion in distal femur: first Ddx = Osteosarcoma
T/F Localized bone destruction can be focal or multifocalTrue
Who generally gets neoplasia?Middle-aged to older
Sites more prone to primary bone tumors (esp osteoSA)Proximal humerus, distal radius, distal femur, proximal tibia (Away from the elbow, towards the stifle)
Abnormal bone growth: physeal location = Rickets (vitamin D deficiency)
What does rickets look like?Widening of physes (failure of ossification)
Flaring of metaphyses
Extra complication with rickets?Asynchonous growth of radius and ulna (angular limb deformities)
Concurrent nutritional hyperPTH --> generalized osteopenia
Bone tissue destruction: metaphyseal location = Primary bone tumor
HOD (hypertrophic osteodystrophy)
Hematogenous bone infection in skeletally immature
Metastatic bone tumor
Bone tissue destruction: diaphyseal location = Metastatic bone tumor
Hematogenous bone infection in skeletally mature
Discontinuity or destruction of the cortex is a sign of what?Aggressive bone lesions (weakens capacity to provide structural support --> pathological fractures)
What often accompanies a bone tumor?Soft tissue swelling & periosteal reaction
(Example: destructive, epiphyseal monostotic lesion involving subchondral bone of proximal tibia)(SCC)
(Example: destructive, metaphyseal polyostotic lesion of claw in young bovine)(Hematogenous bone infection (osteomyelitis), possibly from umbilicus)
(Example: destructive, metaphyseal polyostotic lesion of raduis & ulna in young dog)(HOD: band of radiolucency in metaphyses, cuff-like periosteal new bone, 'double physes')
(Example: destructive and expansive, diaphyseal monostotic lesion in canine metatarsus)(Enchondroma: short transition zone, smooth outline)
(Example: focal destructive, diaphyseal monostotic lesion with sequestrum in equine metatarsus)(Focal osteomyelitis from puncture wound. Periosteal reaction & ST swelling)
(Example: destructive, midshaft polyostotic lesion in canine ilium & other bones)(Undifferentiated carcinoma; +exuberant periosteal new bone, cortical destruction)
Navicular syndrome looks likeFocal, cystic, well defined, short zone of transition
Zone of transition for non-aggressive lesions looks likeDistinct (e.g. benign enchondroma)
Zone of transition for aggressive lesions looks likeIndistinct (permeative) (e.g. osteosarcoma)
Patterns of focal bone destruction (3)Geographic
Moth-eaten
Permeative
Zone of transition refers to area betweenNormal bone and unhealthy
Geographic pattern of focal bone destruction looks likeSingle area, clearly marginated, narrow zone of transition
+/- sclerotic margin, thin cortex
Examples of lesions with focal geographic pattern(Benign/non-aggressive, low grade lesions)
Bone cyst
Pressure atrophy
Benign dental tumor
What do bone cysts look like?Well-defined, round/oval, thin sclerotic margin
Moth-eaten pattern of focal bone destruction looks likeMultiple areas of osteolysis (can coalesce), less well-defined, wider zone of transition
Cortex irregularly eroded
Examples of lesions with moth-eaten geographic pattern(More aggressive disease)
Malignant neoplasia
Osteomyelitis
Permeative pattern of focal bone destruction looks likeNumerous pinpoints, poorly defined margin, wide zone of transition
Cortex irregularly eroded, hard to see in medulla
Examples of lesions with permeative geographic pattern(Highly aggressive disease)
Active malignant neoplasia (osteoSA)
Fulminant (fungal) osteomyelitis
Increased bone density: Cortical thickening e.g.Chronic hypertrophic osteopathy
Increased bone density: Periosteal new bone e.g.Trauma, bone infection
Increased bone density: Endosteal/medullary new bone e.g.Panosteitis, osteosclerosis, bone infarcts
Increased bone density: Cancellous new bone formation e.g.Bone abscess
Increase bone density lesion distribution: Generalized & polyostotic e.g.Osteopetrosis
What does osteopetrosis look like? May lead to?Increased opacity of medulla (osteoclastic dysfunction)
Loss of hematopoietic function
What can happen with cats after leukemia virus infection?Generalized osteosclerosis --> non-regenerative anemia
Increase bone density lesion distribution: Focal & polyostotic e.g.Panosteitis
Increase bone density lesion distribution: Multifocal & mono/polyostotic e.g.Metastatic tumor
Bone infarct
Increase bone density lesion distribution: Focal & monostotic e.g.Healing fracture (>1 bone can be involved)
Bone infarct
Panosteitis lesion localizationFocal, polyostotic, endosteal, diaphyseal
Classic lesion of panosteitis? (CS?)Thumbprint in diaphysis (CS = shifting lameness, usually in immature)
Fungal infection lesion localizationFocal, polyostotic, endosteal & periosteal, diaphyseal
Craniomandibular osteopathy: occurs in who? CS?Cairn, West Highland terrier
Painful opening mouth, difficulty eating (usually resolves by adulthood)
What does craniomandibular osteopathy look like radiographically?Bony proliferation around mandibles & tympanic bullae, no evidence of bone destruction
How does a combination of lytic & proliferative patterns look radiographically?Usually productive process superimposed over destructive
New bone formation can obscure osteolysis
Superimposition of irregular new bone creates relative radiolucency
Example of 2 pathological processes that can be lytic & proliferative simultaneouslyDJD & synovial cell sarcoma
Additional tests required for lytic & proliferative lesionsBiopsy, further tests, follow-up radiographs
Ultrasound-guided FNA sometimes gives cytological dx
Examples of lesions that can be lytic & proliferativeFungal infection (slow pattern of development), primary bone tumor, sequestrum (complication of osteomyelitis or focal bone necrosis)
What does a sequestrum consist of?Sclerotic piece of necrotic bone surrounded by cloaca, with a discharging sinus. Surrounding bone (involucrum) is sclerotic w/ palisading periosteal reaction
How fast does a malignant bone lesion progress?3.5 weeks
Summary of non-aggressive lesionsShort zone of transition (distinct margins, sclerotic border, geographic lesions)
Intact cortex +/- displaced, thin
Smooth, continuous periosteal new bone
Static/slow change in appearance
Summary of aggressive lesionsLong zone of transition (indistinct margins, no sclerosis, moth-eaten/permeative lesions)
Interrupted cortex
Irregular periosteal new bone
Rapid change in appearance
How should lesions with mixed appearance be judged? What is needed for diagnosis?Judged by most aggressive feature
Must have biopsy and/or culture for diagnosis!
Primary bone tumor: age? mono- or polyostotic? Location in bone?Any age
Monostotic
Metaphysis
(Likely to have periosteal rxn)
Metastatic bone tumor: age? mono- or polyostotic? Location in bone?Old
Polyostotic
Metaphysis or diaphysis
Mycotic osteomyelitis: age? mono- or polyostotic? Location in bone?Young
Polyostotic
Metaphysis
Bacterial osteomyelitis (hematogenous): age? mono- or polyostotic? Location in bone?Young
Polyostotic
Metaphysis
Bacterial osteomyelitis (inoculation): age? mono- or polyostotic? Location in bone?Any age
Monostotic (+/- adjacent bones)
Any part of bone
HIGHLY LIKELY to have periosteal reaction
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