CHEST/MSK Flashcards
PCOS criteria
polycystic ovarian morphology with clinical and endocrine dysf(x)
- >25 follicles/ovary
- >10 cc Ov vol
- peripheral follicles, ‘string of pearls’
often b/lateral, sometimes unilateral.
insulin resistance, androgen hypersecretion
what lobe hypertrophies in budd chiari?
caudate
ow is chemical fat saturation achieved?
applying a narrow bandwidth 90° pulse specific for Larmor frequency of fat followed by a excitation pulse
dysmorphic liver (scarring/distortion) with biliary tree dilation DDx
PSC
cholangioCA
PV thrombophlebitis (mimic - thrombosed veins mimic dilated ducts)
DDx small calcified renal lesions
renal calculi
vascular calcs
calcified renal lesion (cysts, masses)
renal papillary necrosis
recurrent renal infections (also TB)
nephrocalcinosis
medullary sponge kidney
nephrocalcinosis subtypes
medullary and cortical
causes of medullary calcinosis
usually hyperPTH, RTA, medullary sponge kidney
medullary calcinosis features
punctate Ca2+ localized to renal pyramids; usually extensive and bilateral
+/- calcs in collecting system
kidneys usually normal size/function
nephrocalcinosis causes and features
shock, hypotension
small kidneys, irregular cortical calcs, often impaired Fx
medullary sponge kidney multiple calcs in dilated tubules
multiple tiny calcs in dilated tubules
dilated tubules best seen on the pyelographic phase
what is a reverse Bankart?
detachment of the posteroinferior labrum with avulsion of the posterior capsular periosteum
Bankart lesion definition
injuries to the anteroinferior aspect of the glenoid labral complex
- Bankart: injury to labrum and GH capsule/ligs.
- Bony bankart involves # of the AI glenoid
Perthes lesion
chondrolabral detachment with periosteal stripping of the scapula; the labral fragment remains attached to periosteum
what is ALPSA
anterior labroligamentous periosteal sleeve avlusion
- labral tear remaining attached to periosteum of glenoid
GLAD
glenolabral articular disruption
- labral tear with anteroinferior articular cartilage injury `
ALSA VS PERTHES
both labral tears with the labral fragment remaining attached to periosteum.. ALPSA (anterior labroligamentous periosteal sleeve avulsion) is displaced
Segond vs Arcuate sign
segond: avulsion of anterolateral tibia (more medial and anterior fragment)
arcuate sign: fibular head avulsion
arcuate uterus
incomplete absorption of the uterovaginal septum. MILD anomaly.
- mild, smooth indentation in the fundal endometrium with NORMAL OUTER CONTOUR
didelphys uterus
Duplication of the uterinne horns, and duplication of cervix.
fundal cleft >1CM
bicornuate uterus
partial fusion failure of the paramesonephric ducts resulting in uterus divided into 2 horns.
- bicollis = 2 cervixes.
- unicolis = 1 cervix
bilateral diffuse nodular heterogeneity with fine calcs in parotid gland
Sjogren’s. also RA, SLE, SS
what is the urachus?
remnant of fetal allantoic stalk; connection btw bladder dome and umbilicus
reasons to treat renal AML?
size, hemorrhage
causes of SVC occlusion
central venous catheters
malignancy
What is May-Thurner syndrome?
compression L CIV by right CIA
common presenting symptom of renal A aneurysm
hypertension (commonly they get microemboli)
what is Budd Chiari?
congestive hepatopathy 2/2 hepatic vein occlusion
calcified soft tissue mass differential
dystrophic calcification
MO/HO/injection granuloma
focal - phlebolith, arterial calc
metastatic calcification (due to elevated serum calcium)
osteosarc, synovial osteochondromatosis
what is synovial osteochondromatosis (aka osteochondromatosis)
primary or secondary
loose intra-articular cartilagenous bodies which may/not be calcified
Primary synovial chondromatosis is ? what joints?
self-limiting, benign process characterized by synovial metaplasia and proliferation resulting in intra-articular cartilaginous loose bodies
- knee (70%), hip (20%), elbow/shoulder
secondary synovial chondromatosis
intraarticular loose bodies secondary to joint pathology (trauma, OA, infection neuropathic osteoarthropathy)
what is a neuropathic (charcot) joint?
progressive degen/destructive joint disorder in pt with altered pain/proprioception
- 2/2 DM, neuro disorders/spine injury, MS, steroid use,
DDx of intra-articular loose bodies
osteochondral # or osteophyte fragment
synovial chondromatosis
meniscal calcification
tenosynovial GCT
osteochondritis dissecans
Osteochondritis dissecans
separation of an osteochondral fragment from the bone, with gradual fragmentation of the articular surface forming OC defect
- associated with intraarticular loose bodies
- associated with repetitive trauma
- MC affecting: knee (95% of all cases are femoral condyle), ankle, capitellum, glenoid
Brown Tumor features
osseous manifestation of HPT; reparative, not neoplastic
- identical to GCT histologically
- common sites: mandible, clavicle, ribs, pelvis.
- well defined, pure lytic lesion without reactive bone changes. osseous expansion but not destructive
DDx for lytic bone lesion
fibrous dysplasia/cortical defect
enchondroma/EG
GCT /BCT
NOF
Osteoblastoma
Met/MM
ACB/UBC
infection/infarction
chondroblastoma
‘rat bite erosion’
gout
gull wing erosion
‘erosive’ OA
multiple enchondromas
Maffuci (soft tissue hemangiomas) and Ollier disease
what are enchondromas
benign tumor of hyaline cartilage originating in medullary bone
enchondroma imaging features
genographically central bone lesion in long bones (50% hands/feet, prox humerus/femur/prox tib), mixed lucent/sclerotic, no complete cortex destruction of ST mass if no path #. on MR - lobulated high SI
DDx: low grade CS
Hypoechoic spleen lesion DDx
infarction, hematoma, abscess, metastasis. lymphoma, lymphangioma (cystic), angiosarcoma, hemangiopericytoma, hemangioendothelioma, littoral cell angioma
splenic metastasis features
usually seen in disseminated metastatic dz (Ov, Breast, lung, CRC, melanoma)
usually multiple hypoechoic masses, may have hyperE rim
Unique feature about subependymoma?
enhancement is unusual!!
round, dense, highly cellular and enhancing mass in the 4th ventricle?
likely medulloblastoma (esp if child)
ATRT can be very similar if <3yo
most common malignant pediatric brain tumor
medulloblastoma
comet-tail sign (lung)
round atelectasis
Sinonasal GPA involvement occurs in ? % of patients
> 75%
sarcoid involves sinonasal cavities in ? % of patients
20%
lumbar region IDEM lesion in adults DDx
myxopapillary ependymoma
meningioma (iso to cord T1, T2, unusually in conus location)
mets
NST
mucinous tumors of the pancreas - what age?
MIDDLE age
imaging features of mucinous panc lesions
usually body-tail
- cystic lesion with fewere and larger internal septations than serous.
- middle age women
serous pancreas cystadenoma
innumerable microcysts in encapsulated pancreastic mass.
elderly
what is SAPHO?
synovitis, acne, pustulosis, hyperostosis, osteitis
- rare chronic inflammatory d/o of skin, bone, joints
what is Lofgren’s syndrome?
acute clinical presentation of systemic sarcoidosis
- fever, erythema nodosum, bilateral hilar LA
avascular necrosis of the navicular in peds vs adults - name?
Peds: Kohler’s disease
Adults: Muller-Weiss
deforming non-erosive arthropathy (Jacoud’s) is?
marked ulnar deviation MCP, reducible
associated with SLE, PsA,
typical findings of gout
mono or poly articular, asymmetric.
tophi/soft tissue changes are late findings
para-articular eosions - ‘punched out’, well defined with sclerotic borders
normal mineralization and JS preserved.
central erosions
erosive OA
paracentral (both sides of the joint) erosions
PsA (Mickey mouse)
marginal erosions
RA
hemophilic arthropathy
polyarticular process but can be asymmetric
radiodense ST swelling/effusion
osteoporosis/penia, subchondral cystic changes
erosive bone changes, and late stage joint space loss and subluxation
fixed humeral head in internal rotation –> think what?
posterior dislocation!
reverse bankart
impaction fracture of the posterior glenoid
associated with reverse Hill - Sachs
posterior ankle impingement (os trigonum syndrome)
FHL tenosynovitis and increased signal around the os trigonum
synovial osteochondromatosis
ossification/calcification of the nodules (bening neoplastic/proliferative nodules of the synovium)
primary (idiopathic) and secondary (OA related) forms
DDx: PVNS, synovial hemangioma, lipoma arborecens
synovial chondromatosis
nodularity and proliferation of the synovium, (initial/tranwitional phase of the osteochondromatosis - the 3rd stage is calcification)
Sprengle’s deformity
complex congenital deformity of the scapula
elevated/winged scapula - unilateral or bilateral
- associated with Klippel-Feil syndrome, omovertebral bone (cartilage or bone connection between cervical spine and scapula)
Blount’s disease findings
congenital tibia vara
osteochondrosis of the the medial proximal epiphysis of the tibia
DDx pediatic tibial bowing
Developmental
Ricket’s
Blount’s disease
Osteogenesis imperfecta
osteomyelitis
picture frame vertebra
cortical thickening of the vertebral body = Paget’s disease
Maffucci syndrome
congenital non-hereditary mesodermal dysplasia
multiple enchondromas and soft tissue malformations (venous, spindle-cell hemangiomas)
lipomatous infiltration of pancreas
cystic fibrosis
Shwachman-Diamond syndrome - rare, AD disorder (pancreatic insufficiency, skeletal malformation/metaphyseal chondrodysplasia, bone marrow hypoplasia)
ollier’s disease
multiple enchondromas
adult with painful enchondroma?
malignant degeneration to chondrosarc
enlarged EOM + diffuse periostiitis - think of what?
Grave’s thyroid acropachy
DDx symmetric diffuse periosiitis
- PsA, RA, JIA
- thyroid acropachy, hypertrophic osteoarthropathy
- hypervitaminosis A, fluorosis
- CMRO
DDx symmetric diffuse periosiitis
- PsA, RA, JIA
- thyroid acropachy, hypertrophic osteoarthropathy
- hypervitaminosis A, fluorosis
- CMRO
periosteal reaction of the long bones without an underlying bone lesion is ?
hypertrophic osteoarthropathy
Parsonage Turner
self limiting acute idiopathic brachial neuritis
split fat sign
lesion within the neurovascular bundle -> nerve sheath tumor (Schwannoma and neurofibroma)
NF1 findings
skull: sphenoid defect, suture defects
scoliosis/kyphysos
vertebral scallopinnng
bowed tibias
neurofibroma / NSTs
pseudoarthrosis
soft tissue calcifiation categories (2)
metabolic vs dystrophic (some sort of muscle injury/trauma)
dystrophic soft tissue calcifications
HO/MO, injection granuloma, parasitic infections
metabolic soft tissue calcifications
inflammatory APs
renal osteodystrophy
sclero/dermatomyositis
progressive massive fibrosis DDx
sarcoid
silicosis
coal worker’s pneumoconiosis
talcosis
progressive massive fibrosis
coalescence of nodules into a mass with calcifications and associated architectural distortion
bronchial atresia
area of bronchus that does not communicate with the tracheobronchial tree. often mucus clogged
area of hyperexpanded hyperlucent lung.
Broad differential for mid to upper lung predominant ILD (SHORTI)
sarcoid, HP, occupational exposure, radiation fibrosis, TB/fungal, idiopathic pleuroparenchymal fibroelastosis
Lower lung predominant ILD - broad ddx
UIP NSIP HP (very unlikely to be occupational, TB/Fungal, IPPFE)
broad NSIP pattern
peribronchial, subpleural sparing, diffuse GGO without traction bronchiectasis and honeycombing
IUP broad pattern
basal predominant reticulations, honeycombing, traction bronchiectasis
central/peribronchial ILD - broad DDx
sarcoid, NSIP, HP, OP
peripheral/subpleural ILD broad DDx
UIP, NSIP, HP, OP
typical pulmonary fibrotic HP major features
usually - upper lung predominant (but can vary depending on acuity!!)
coarse reticulations, non-dominant traction B and honeycombing. ill-defined centrilobular nodules and GGOs, mosaic attenuation
Mosaic attenuation DDx
associated with obstructive small airway dz (CF, bronchiolitis)
occlusive vascular dz (chronic PE)
parenchymal dz
definition of HP
group of immune-mediated pulmonary disorders causing inflammatory/fibrotic reaction of the lungs
- fibrotic and non-fibrotic types
ABPA
overreactive immune response to aspergillus antigen in pts with asthma / CF
- high density central mucus plugging and bronchiectasis
- later stages = fibrotic changes
isolated air trapping DDx
asthma, stem cell transplant, bronchiolitis obliterans, GPA
constrictuve bronchiolotis
small airway occlusion and destruction
seen in stem-cell tx GVHD, lung transplant rejection, inhalation disease, autoimmune disease, infectious causes (mycoplasma)
DDx hyperlucent right lung
aspirated FB (put pt in decub)
Poland syndrome
Swyer-James syndrome
large bulla
emphysema
PTX
crazy paving pattern ddx
pulmonary hemorrhage, alveolar proteinosis, pcp, pul edema
UIP categories
typical, probable UIP, indeterminate, alternative
typical UIP
basilar, subpleural, heterogenous, sometimes diffuse.
honeycombing + reticulation + TB
probable UIP
basilar, subpleural.
reticulation, TB, +/- GGO. NO honeycombing.
indeterminant for UIP
basilar and subpleural, but sutble findings - mild GGO, some features of fibrosis but no specific etiology
alternative Dx to UIP
upper/mid lung, peribronchovascular/perilymphatic
no fibrotic changes
4 most common causes cystic LD?
Lymphangiomyomatosis
pulmonary LCH
lymphocytic interstitial PNA
BHD
LAM (lymphangiomyomatosis) demographics
female, typically reproductive ages
UNLESS tuberous-sclerosis LAM complex
LAM imaging features
THIN WALLED uniform shape, diffuse distribution, normal intervening lungs
Associated findings: AMLs (liver/kidney/retroperitoneal), chylous PEff
cystic lung disease in female, 40, thin wall, uniform distribution and shape .. likely cause?
LAM
what is LAM?
diffuse of smooth muscle proliferation in the lungs
AMLs are associated with?
LAM, TS, or TS-LAM!
LAM-TS complex
similar genetic defect; overlapping features with lam and TS - cystic LD, AML, sclerotic bone lesions, myocardial deposition of focal fat
Characteristic pLCH features
upper lung predominant cysts, spares costophrenic <)
- thin and thick walled cysts, bizzare shaped, pulmonary nodules (parenchymal abn)
- associated with smoking.
- can px with spontaneous PTX
pLHC progression of nodules
nodules –> cavitation –> cystics –> coalescence of cysts with intervening fibrosis
LCH osseous manifestations?
aggressive appearing lesions, lytic and destructive. the bone can sometimes reform
cystic lung disease sparing the costophrenic angles?
pLCH
Lymphocytic Intersitial PNA features
- benign lymphoproliferative dz
-oligocystic, thin walled cysts, lower lung predominant - GGOs can be present
- centrilobular nodules may be present
LIP connective tissue and autoimmune associations
Sjogren, RA, HIV, Castleman’s
oligocystic, lower lung predominant cystic lung disease
Lymphocytic interstitial PNA
Sjogren’s disease and LIP associated with what?
primary lung lymphoma
what cystic lung disease presents with PTX?
BHD, pLCH, LAM
BHD features
<20 thin walled cysts (can be a SINGLE cyst)
- ovoid/lentiform/ellipsoid shape, associated with fissures/pleura
lower lung predominant
BHD triad
lung cysts
renal tumors
skin fibrofolliculomas
oligocystic lung diseases
BHD, LIP
differential for epiphyseal bone lesions
osteochondroma
chondroblastoma (peds)
GCT (adult)
ABC
OM
metaphyseal bone lesions
osteochondrona
FCD/NOF
chondromyxoid fibroma
ABC
encondroma
UBC
FD
OM
osteosarc
diaphyseal bone lesions
osteoid osteoma
chronic OM
FD
LHC
adamantinoma
osteofibrous dysplasia
multiple sclerotic lesions in bone
osteopoikolosis
treated mets
Bone forming tumors - benign DDx
bone island (enostosis), osteoid osteoma
enostosis definition
benign lesion of normal cortical bone, in abnormal location
bony spicules dense, with normal outline
osteoid osteoma
<30, night pain, disproportionate pain to lesion size
- femur/tibia/posterior elements (painful scoliosis!)
- tumor = nidus. surrounded by reactive sclerosis
- cortical, medullary, subperiosteal
- intra-articular lesions can cause joint effusions and mimic OA!
osteoblastoma
large osteoid osteoma like lesion (>1,5 cm)
- posterior elements and sacrum
- can be aggressive appearing (mixed lucent/sclerotic)
- long bones - more likely to be OO
osteogenic sarcoma
usually young, M>F,
femur/tibia/humerus
mixed sclerotic/lucent
aggressive periosteal reaction (Codman’s triangle)
Osteogenic sarcoma subtypes
conventional
telangiectatic
small cell (looks like FD/FCD!)
low grade central
secondary (to prior radiation)
juxtacortical type (parosteal, periosteal, high grade surface)
juxtacortical osteosarcoma types
parosteal, periosteal, high grade surface
chondrogenic bone tumors - bening DDx
OC
chondroma / enchondroma,
osteochondromyxoma
BPOP (bizarre parosteal osteochondromatous proliferation)
subungual exostosis
chondrogenic bone tumors - intermediate/local aggressive
chondromyxoid fibroma, low grade chondrosarc
osteochondroma
bony exostosis, continuous with medullary space
cartilage cap thickness important (solitary = low risk, multiple/hereditary types much higher)
chondroma subtypes 2
= central (enchondroma), periosteal (juxtacortical)
enchondroma
MC tumor of small bones hands/feet
expansile lucent, some sclerosis
usually asx solitary, may #
multiple (Maffucci/Olliers - malignant risk)
chondroblastoma
RARE, teens, painful
epiphyseal OR apophyseal, femur most common, also talus and patella
- usually sharp lytic lesion, +/- sclerotic border. matrix 1/3
- on MRI, often lots of BM edema
DDX CLEAR CELL CHONDROSARC
chondromyxoid fibroma features
extremely rare. <30
any bone, MC prox tibia
lobulated/oval eccentric lytic lesion, expansile, well defined sclerotic margin in 85%. geographic bone destructionn
no matrix, periosteal rxn
DDx ABC, GCT, chondroblastoma/NOF in younger
chondrosarc - location & key features
pelvis, long bones, ribs
- may have cartilagenous matrix
larger than enchondromas, endosteal scalloping, periosteal rxn, soft tissue component
Fibrous tumors - MSK DDx
desmoplastic fibroma (desmoids of bone), fibrosarcoma
NOF/FCD
bening fibrous histiocytoma of bone
FCD/NOF
NOF is larger, medullary
FCD smaller, cortically based
seen in peds, not in adults (not exclusive)
GCT features
benign but locally aggressive.
ENDS of long bones. NO matrix. expansile, sharp margins
NO sclerotic border
chordoma
malignant fibrous lesion, soft tissue component
sacrum and clivus
ABC features
multiloculated blood-filled, cystic lesion
fluid-fluid levels.
can be primary or arise from GCT/FD/chondroblastoma
expansile, can grow fast, look aggressive
UBC features
usually prox metadiaphysis long bones, usually <20
pathologic # = fallen fragment
fibrous dysplasia
preference for long bones
expansile lesion with usually GG matrix
monostotic MC, polyostotic with hormonal syndromes
MSK LCH
solitary or multiple. variable appearances
aggressive in long bones. in skull, well defined with beveled edge.
consider in any lesion
intraosseous ganglion/geode
articular ends of long bones. geode if associated with degeneration of the joint
Ewing features
<20 usually. diaphysis and flat long bones
aggressive, permeative appearance
soft tissue compontnt
adamantinoma
low grade malignant lesion
usually 20-30yo, prox tibia (anterior cortex!), but also jaw, hands, feet
multilocular (often), slightly expansile, osteolytic lesion with areas of sclerosis, lack periosteal reaction
undifferentiated high grade pleomorphic sarcoma
long bone meta/diaphysis
brown tumor features
primary (HPTH) or secondary (renal failure)
represents a reparative cellular process
cellularly identical to GCT
Sites: mandible, clavicle, ribs, pelvis.
XR: well defined, pure lytic lesion without bone rxn. may thin/expand cortex
DDx: GCT, FD
diffuse centrilobular micronodules
nTB/mTB infection, HP, RB-ILD, pneumoconioses, endobronchial tumor spread
NSIP features - histology
less common than UIP, histo - homogenous inflammation or fibrosis (UIP is heterogenous)
- cellular and fibroitic
- common pattern in collagen vascular diseases
cellular NSIP
GGO alone, or GGO + reticulationsparing of the immediate subpleural lung is highly predictive for NSIP
fibrotic NSIP
GGO+ reticulation +/- traction bronchiectasis
what finding is highly specific for NSIP
immediate subpleural sparing
RB-ILD/DIP association?
almost all smoking related
RB + symptoms =?
RB ILD
treatment for RB ILD/DIP
STOP SMOKING
steroids
RB ILD features
intraalveolar macrophages with little fibrosis
GGO, small nodules (ill defined, centriblobular), no particular distribution
DDx for pulmonary consolidation
Dependent on symptom duration
acute: PNA, edema, hemorrhage, diffuse alveolar injury
Chronic: OP, chronic eosinophilic PNA, mucinous adenoCA
organizing PNA features - clinical
granulation tissue and patchy PNA
idiopathic, infection, fumes
presents with cough, SOB, fever
Organizing PNA imaging features
patchy multifocal airspace consolidation/GGOs - often irregular shape
large nodules/masses 15%
peripheral and peribronchial distribution
fibrosis - uncommon, mild.
Atoll (reverse halo) sign - ring shape externally and black inside; highly predictive
progressive massive fibrosis
formation of large mass-like conglomerates
predominantly upper lobes
associated with pneumoconioses (coal worker and silicosis)
chronic eosinophilic PNA
idiopathic/known antigen, present with months of cough, SOB, low grade fever
50% have hx asthma. peripheral eosinophilic common.
identical to OP on CT - peripheral GGO, consolidation, upper lobe predominance.
responsive to steroids.
GGO DDx
acuity of symptoms dependent:
acute: edema, hemorrhage, atypical PNA, diffuse alveolar injury
chronic: interstitial PNA, HP, chronic eosinophilic PNA, OP, atypical infection, alveolar proteinosis
subacute HP features - clinical and imaging
acute, subA and chronic stage
most show in subacute stage: alveolitis - diffuse/patchy GGO, peribronchiolar granulomas (centrilobular nodules), cellular bronchitis (mosaic perfusion)
chronic HP features
reticulation and traction bronchiectasis (no honeycoming, no subpleural predominance)
- upper lobes involved most severely
perilymphatic nodule location
subpleural.
paraseptal and perifissural.
peribronchovascular
perilymphatic nodules ddx
sarcoid
lymphangitis spread tumor
silicosis and CWP
amyloid
LIP
sarcoid stages on CXR
0 - normal xr
1- hilar LA
2 - hilar LA + pulmonary nodules
3 - lung findings only
4- fibrosis
sarcoid is associated with?
aspergillomas!
differential for sarcoid
silicosis, CWP, end stage fibrosis
random nodules description
everywhere. no predominant pattern, uniform distribution throughout lung
random pulm nodule DDx
miliary TB and fungal
hematogenous mets
sarcoid as well!
centrilobular nodules description
most peripheral nodules will be 5-10 mm away from pleura!
appears diffuse and uniform, but none at the pleural surface
multiple nodules ->
- subpleural nodules present: if patchy/nonuniform -> perilymphatic. diffuse and uniform -> random.
- no subpleural -> centrilobular
/
centrilobular nodule DDx
small airways disease: bronchiolitis
endobronchial spread of TB/MAC
HP
RB-ILD
endobronchial tumor spread (mucinous)
bronchoPNA
penumoconioses
tree-in-bud nodules description
dilation and impaction of centrilobular airways, very common/likely to be infectious
centered peripherally 5-10mm from pleura
associated with centrilobular nodules
tree in bud nodule ddx
endobronchial TB/MAC
bronchitis/bronchiolitis/bronchoPNA
CF
aspiration
ABPA
centrilobular emphysema description
upper lobe predominant centrilobular lucencies (enlargement of the airspace with destruction of the alveolar walls)
without defined cyst walls
panlobular emphysema description
destruction and expansion of the airspace involving entire secondary pulm lobule, diffuse or basal-predominant lucency/loss of lung architecture
(associated with alpha 1 ATD, swyer-james)
paraseptal emphysema description
morphological subtype of emphysema with lucencies adjacent to the pleural surface measuring up to 10mm. above = subpleural blebs
Pulmonary emphysema is defined as ?
abnormal permanent enlargement of airspaces distal to the terminal bronchioles accompanied by destruction of the alveolar wall, without obvious fibrosis
lung cyst vs emphysema?
cysts have a defined wall.
ddx for pulmonary cysts
honeycombing
emphysema
pneumatocele
HP (rare)
pLCH
LAM/TSLAM
LIP
BHD
direct & indirect signs of atelectasis
Direct: band-like lung tissue, movement of fissure, vessel crowding
Indirect (movement of other structures): shift of mediastinum/hilum/diaphragm, rib crowding
4 types of atelectasis
obstructive (gas absorbed but not replaced)
relaxation (passive)
adhesive (surfactant deficiency)
cicatricial (archiectural distortion)
