Review Note
Last Update: 02/18/2024 05:30 AM
Current Deck: Part 2::6. High Yield Questions::Sarcoma
PublishedCurrently Published Content
Front
Write brief notes on the epidemiology, microscopy, immunohistochemistry and cytogenetics of extraosseous Ewing's sarcoma/PNET
Back
Epidemiology: approx. 10% of all cases of Ewing’s, bimodal age distribution (peaks <5 and >35 years) with slightly older median age than skeletal Ewing’s, no racial or gender predisposition.
Microscopy: monomorphic, small, round blue cells that contain large spherical nuclei, inconspicuous nucleoli and indistinct cytoplasmic borders. These cells lack extracellular matrix and have low mitotic activity, albeit necrotic areas are commonly observed.
IHC: positive for CD99, NKX2.2, vimentin
Cytogenetics: most common translocation is t(11;22)(q24;q12), resulting in EWSR1-FLI1 fusion (~85 - 90%), second most common is t(21;22)(q22;q12), resulting in EWSR1-ERG fusion (~5 - 10%)
Further information, not for memorising (no card)
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