Case 8: AML with t(1;22)
AML (megakaryoblastic) with t(1;22) occurs in infants and young children less than 3 years old
1991 paper with more information: https://pubmed.ncbi.nlm.nih.gov/1859887/
The blasts in AML with t(1;22) have megakaryoblastic:
- morphology, e.g cytoplasmic blebbing -- apologies, this case did not have a good example of that (but did of course have the translocation)
- immunophenotype, hence positivity for CD61 and CD41a, and negativity for MPO
Major consideration on differential diagnosis is AML a/w Down syndrome, which would not show the translocation but have a GATA1 mutation
The RMB15::MKL1 fusion is associated with t(1;22)
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— Clarissa E. Jordan, MD (@pathcejmd) March 16, 2022
Another AML subtype! Blasts are CD41a+ and CD61+ by flow, MPO- on cytochemical staining
What is the typical age group for this leukemia? (Poll⬇️)#PathTwitter #MolecularPath #MedEd @MayoClinicPath
(P.S. Always learning - I welcome any feedback!) pic.twitter.com/7fhf009R8c