MORPHOLOGY AND GENETICS – QUICK CORRELATION IN ACUTE MYELOID LEUKEMIAS (AML)

Acute myeloid leukaemia with defining genetic abnormalities Include the following categories according to WHO 2022 Hematolymphoid tumors- 5th edition.

  • Acute pro-myelocytic leukaemia with PML::RARA fusion Acute myeloid leukaemia with RUNX1:: RUNX1T1 fusion
  • Acute myeloid leukaemia with CBFB::MYH11 fusion Acute myeloid leukaemia with DEK::NUP214 fusion
  • Acute myeloid leukaemia with RBM15::MRTFA fusion
  • Acute myeloid leukaemia with BCR::ABL1 fusion
  • Acute myeloid leukaemia with KMT2A rearrangement Acute myeloid leukaemia with MECOM rearrangement Acute myeloid leukaemia with NUP98 rearrangement
  • Acute myeloid leukaemia with NPM1 mutation
  • Acute myeloid leukaemia with CEBPA mutation

Each of these mutations have certain specific morphological features.

Some of these morphological features are nonspecific, while some are specific.

A few such unique morphological findings are discussed here.

1. Acute promyelocytic leukaemia (APL) with PML::RARA fusion

2. Acute myeloid leukaemia with RUNX1::RUNX1T1 fusion

Blasts are large, with abundant basophilic cytoplasm perinuclear clearing (hof). Few blasts contain large Chédiak–Higashi–like granules. Auer rods are frequently found and appear as a single long rod with tapered ends.

Acute myeloid leukaemia with RUNX1::RUNX1T1 fusion

3. Acute myeloid leukaemia with CBFB::MYH11 fusion

Eosinophils have immature granules. These granules are often abnormally large and are distinctly dark purple-violet (unlike the usual. bright orange granules in eosinophils)

Acute myeloid leukaemia with CBFB::MYH11 fusion

4. Acute myeloid leukaemia with RBM15::MRTFA fusion

Blasts have megakaryocytic differentiation. Megakaryoblasts are usually medium-sized to large, with a round, irregular, or convoluted nucleus. The cytoplasm is often agranular and basophilic, and it may have blebs.

Acute myeloid leukaemia with RBM15::MRTFA fusion

5.Acute myeloid leukaemia with CEBPA mutation

Bone marrow and peripheral blood show increased blasts with or without maturation. Erythrophagocytosis is characteristic for this genetic aberration.

Acute myeloid leukaemia with CEBPA mutation

6. Acute myeloid leukaemia with NPM1 mutation

Blasts with cup-like nuclear morphology are strongly associated with the presence of NPM1 and FLT3 ITD mutations. Identification of this finding in > 10% of blasts is highly specific for AML with NPM1 mutation.

Acute myeloid leukaemia with NPM1 mutation

7. Acute myeloid leukaemia with DEK::NUP214 fusion

Bone marrow smears show increased blasts with maturation or with myelomonocytic differentiation. Multilineage dysplasia is common.

8. Acute myeloid leukaemia with KMT2A rearrangement

Associated with a broad range of blast morphology and myeloid differentiation, with most cases having monocytic, monoblastic, or myelomonocytic features.

9. Acute myeloid leukaemia with MECOM rearrangement

Blasts in the bone marrow have variable morphology, often resembling those seen in AML without maturation, acute myelomonocytic leukaemia, or acute megakaryoblastic leukaemia. Multilineage dysplasia is common

FOR MORE CONCISE NOTES LIKE THESE

SUMMARY OF THESE FINDINGS


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