Msk Bone Lesions - New And Improved

Front 1

where does osteosarcoma occur within bone

Back 1

site of rapid bone growth

Front 2

where does Ewing sarcoma occur within bone

Back 2

follows red marrow distributlion

Front 3

examples of epiphyseal equivalents

Back 3

greater troch
tibial tubercle
patella
carpals
tarsals
glenoid
SI joint

Front 4

what are features of the borders of a lesion that are non-aggressive

Back 4

sharp margins
narrow ZOT
(esp if borders are sclerotic)

Front 5

types of periosteal rxn

Back 5

unilamellated (slow-growing)
multilamellated
spiculated/hair on end
codman triangle (highly aggressive)

Front 6

codman's triangle
classic assoc

Back 6

elevation of periosteum from cortex, forming na angle
classically assoc with osteosarcoma, but really can be assoc with any aggressive process

Front 7

if a lucency is seen in a bone and is 2/2 malig, explain pathophys
if there is a sclerotic lesion, then from

Back 7

osteoclast activity
osteoblast activity

Front 8

appearance of a chondroid matrix

Back 8

varies, can be stippled, flocculent, or have rings and arcs

Front 9

appearance of a bone forming matrix

Back 9

can be fluffy, amorphous, or have cloudlike mineralization

Front 10

size criteria for NOF and FCD

Back 10

>3 cm, NOF
FCD <3cm

Front 11

when does the risk of an enchondroma increase to actually being a chondrosarc

Back 11

if >4-5cm

Front 12

benign lesions that can have a soap bubble appearance

Back 12

ABC
NOF
CMF
brown tumor
hemophiliac pseudotumor

Front 13

malignant lesions that can have soap bubble appearance

Back 13

mets
plasmacytoma
telangiectatic osteosarcoma

Front 14

location of chondromyxoid fibroma

Back 14

rare metaphyseal lesion that can extend to epiphysis

Front 15

what is multiple hereditary exostosis assoc with

Back 15

increased risk of chondrosarcoma

Front 16

MR appearance of multiple hereditary exostosis

Back 16

int T1, int/high T2

Front 17

is bone marrow edema assoc with giant cell tumor

Back 17

not unless fx'd

Front 18

location within bone of osteosarcoma

Back 18

usually metaphyseal

Front 19

location within bone of Ewing sarcoma

Back 19

usually diaphyseal

Front 20

age of pts who get osteosarcoma

Back 20

<30 yo
secondary osteosarcoma in paget's disease or 2/2 radiation

Front 21

how does parosteal osteosarcoma differ from regular osteosarcoma

Back 21

parosteal osteosarc: originates from periosteum and grows outside bone, less aggressive as long as it doesn't invade medullary cavity
conventional osteosarcoma: agressive growth within medullary cavity --> cortical and soft tissue penetration

Front 22

appearance of conventional osteosarcoma

Back 22

often heavily ossified, with dense sclerotic areas, but can have chondroid or lucent matrix

Front 23

what lesions mimic parosteal osteosarcoma

Back 23

cortical desmoid tumor (avulsion injury that is benign but an appear aggressive)
myositis ossificans

Front 24

describe cortical desmoid tumor
common location

Back 24

posteromedial supracondylar ridge of distal femur, 2/2 avulsion of adductor magnus muscle
+/- activity on bone scan
+/- periosteal rxn
DO NOT TOUCH LESION!!!

Front 25

where does ewing sarcoma usually occur

Back 25

diaphysis of long bone (but less often can also be in diametaphyseal and metaphyseal regions and in flat bones)

Front 26

appearance of ewing sarcoma

Back 26

usually permeative but can have partially sclerotic or patchy appearance

Front 27

classic ddx of permative lesion in a child

Back 27

ewing
infx
eg

Front 28

who gets chondrosarc

Back 28

adults >40, rare in children

Front 29

on mr, what features may help lead to a dx of chondrosarc

Back 29

soft tissue mass ro edema in a lesion that looks like enchondroma

Front 30

where do giant cell tumors most commonly metastasize

Back 30

lungs

Front 31

which malig bone tumor can have a sequestrum

Back 31

fibrosarcoma
malig fibrous histiocytoma
desmoid tumor

Front 32

how to differentitate btwn fibrosarc and malig fibrous histiocytoma

Back 32

can be identical to fibrosarc

Front 33

which is more common fibrosarc or malig fibrous histiocytoma

Back 33

MFH

Front 34

other names for desmoid tumor

Back 34

desmoplastic fibroma
aggressive fibromatosis

Front 35

where is desmoid tumor most common

Back 35

in soft tissues

Front 36

appearance of desmoid tumor

Back 36

lytic when in bone (which rarely occurs)
well defined, have benign periostitis with thick spikes
may have bony septa

Front 37

another name for primary lymphoma of bone

Back 37

reticulum cell sarcoma

Front 38

what does primary lymphoma of bone resemble
appearance
how to differentiate

Back 38

ewing sarcoma (permeative, moth eaten)

Front 39

presentation of primary lymphoma of bone

Back 39

pts are usually asx despite having lrg amt of bone involved

Front 40

plasmacytoma

Back 40

lytic bone lesion

Front 41

2 most common soft tissue tumors

Back 41

MFH
liposarcoma

Front 42

t or f:
liposarc must contain fat radiographically

Back 42

false

Front 43

where in body do synovial sarcomas originate

Back 43

adjacent to joints most commonly

Front 44

appearance of synovial sarcoma on MR

Back 44

homogeneously bright on T2 (may be mistaken for fluid clxn)
give gad, to see if it enhances

Front 45

XR appearance of synovial osteochondromatosis

Back 45

multiple calcific loose bodies in joint (pathognomonic)

Front 46

what can synovial osteochondromatosis be confused with sometimes and why

Back 46

PVNS (pigmented villnodular synovitis) b/c in up to 20% of time, teh loose bodies in osteochondromatosis are not calcified

Front 47

is synovial osteochondromatosis benign or malig

Back 47

benign (a do not touch lesion)

Front 48

appearance of pvns on MR and XR

Back 48

marked low signal lining of synovium on T1 and T2 b/c of hemosiderin deposits
lrg erosions

Front 49

ddx pvns

Back 49

osteochondromatosis
hemosiderotic arthritis (rare, from chronic bleeding into a joint)