Clear cell sarcoma - very rare mimic of metastatic melanoma (AIP France 2021 - Case 11)

[@JMGardnerMD]

This video is an excerpt from my one-day dermpath course in Paris, France, on October 8, 2021, for the Academie Internationale de Pathologie - Division Française (IAP French division). Full 5 hour video of the entire course is available for free here: kikoxp.com/posts/8361. WSI Digital slide for this case: kikoxp.com/posts/6792 Handout & figure images for this case: kikoxp.com/posts/8503

[@Jam-zg2co]

thank you immensely, really appreciate all your efforts Dr Gardner . you do not know how you are helping the pathologist all over the world to see cases that never see them , only in books, with an easy and wonderful teaching tips. God bless you. we are really grateful and wishing you a life filled with happiness.

[@evelyne7071]

When attached longitudinally they look like schools of fish. Merci bien. Good point regarding pleomorphism versus translocation; wild recombination variation versus monomorphic population of cancer/sarcoma cells.

[@Jam-zg2co]

Many thanks . it is really amazing session. it is very similar to melanoma even in IHC? so the only way is molecular to differentiate between them? in case the molecular study is not available so how to differentiate between the?

[@vanlalhruaii7303]

Thank you sir

[@RaulRodriguez-sh6vb]

Amazing video

[@RaulRodriguez-sh6vb]

Could you please mention some exception of that rule? Pleomorphism- Complex karyotype and Uniform histology- translocation??

[@mariavictorialaborie560]

Hello Dr. Jerad! Thank you very much, excellent video. It is very helpful for non-expert pathologists. I would like to ask you a question: A clear cell sarcoma, in immunohistochemistry, can it be positive for NSE (neuronal specific enolase)? Morphologically the case is compatible with the diagnosis, but it is located in the dermis and TCS. it is positive for sox10, s100, melanA and NSE (immunohistochemistry available). I was thinking of suggesting FISH and ruling out metastatic melanoma, but I don't know if NSE can be seen in clear cell sarcoma. From already thank you very much !!!

[@JMGardnerMD]

Hi Maria! Thanks for the kind words! NSE is so non specific that I never use it. I don’t know if clear cell sarcoma is NSE positive or not but it wouldn’t surprise me if it was positive. And it wouldn’t change my diagnosis. If I have concern for clear cell sarcoma, I do EWSR1 FISH. hope that helps!

[@mariavictorialaborie560]

@@JMGardnerMD Thank you very much Dr Jerad !!! Yes, I am going to request FISH. it is always very helpful !! thanks for answering !!!