Ewing Sarcoma

Question 1

most common cytogenetic abnormality in EWS

Answer 1

EWSR1-FLI1 (85%)

t(11;22)(q24;q12)

Question 2

second most common cytogenetic abnormality in EWS

Answer 2

EWSR1-ERG (5-10%)

Question 3

tests to identify fusion in EWS

Answer 3

RT PCR
FISH
karyotype

Question 4

area of bone involved with Ewings

Answer 4

usually axial bones, diaphysis (vs metaphysis in osteosarcoma)

Question 5

sites of mets in EWS

Answer 5

lung, bone, bone marrow

Question 6

staging investigation needed in EWS but not osteo

Answer 6

bilateral bone marrows

Question 7

immunohistochemical stains in EWS

Answer 7

CD99+
vimentin+
can have neural differentiation, pseudo homer-wright rosettes, NSE, synaptophysin

Question 8

local control options in EWS

Answer 8

surgery and/or radiation

Question 9

timing of RT/surgery

Answer 9

usually after 12-14 weeks of chemo

Question 10

chemo for EWS

Answer 10

VDC/IE, interval compressed chemo (q2wks)

Question 11

what is the definition of pulmonary metastasis in EWS?

Answer 11

solitary pulmonary nodules greater than 5 mm OR multiple nodules greater than 3 mm