Case Number : Case 1931 - 24 Oct - Dr Arti Bakshi Posted By: Guest

Looks like a myeloid sarcoma/AML...( high magnification shows some eosinophilic precursor cell )

Agree, sheets of dyshesive atypical cells sparing the epidermis, most likely leukemia cutis. Unless clinically known and characterized, a broad IHC panel is indicated to pin down the phenotype and rule out other hematologic malignancies. I would do CD45, CD43, CD34, CD117, lysozyme, CD4, CD20, CD30, CD56 depending upon overall consideration.

Yes, my first though was myeloid sarcoma/AML for IHC

The initial immunoprofile was as following:

LCA positive

CD3, CD20, TdT, MPO, CD117, CD34, CD5, CD30, EBER all negative.

Any suggestions for further immunos/ diagnoses??

CD56? CD123?

CD43 is most sensitive for Leukemia cutis, so I would definitely do that, and also throw in lysozyme.

CD4, CD123, CD56 and TCL1 for BPDCN. 

Yes, this is Blastic Plasmacytoid Dendritic Cell neoplasm.

The tumour cells were diffusely positive for CD4, CD56 and CD123.

Well done to Vincenzo and VParekh!