Submitting Author: Ok, Chi Young, MD
Institution: MD Anderson Cancer Center
Additional authors:Yang O. Huh, MD
Session: AML with recurrent genetic abnormalities Part I

12-year-old female without significant prior medical history

- Chief complaint: upper respiratory infection symptom

- Splenomegaly: 1 to 2 cm below the costal margin

- Laboratory findings

H/H: 11.4/32.6, WBC: 111.2, platelet 17, 96% blasts on differential

Site: Right posterior iliac crest. Method of fixation: formalin-fixed

Microscopic pathology:

Biopsy: Hypercellular (100%) bone marrow with intermediate sized and monotonous blasts with fine delicate nuclear chromatin and occasional starry-sky pattern

Smear: Markedly increased blasts, blasts are intermediate to large in size and show round/oval to slightly indented nuclei, fine chromatin, one or two prominent nucleoli, and small to moderate amount of basophilic agranular cytoplasm. No Auer rods are identified.

Positive stains

Lysozyme (in a subset, 10-20%), CD11c, CD117

Negative stains

MPO, TdT, CD68 (PG-M1)

48,XX,t(2;4;11)(p23;q21;q23),del(3)(q21q27),+der(4)t(2;4;11),add(6)(p11.2),del(12)(p12p13),+13,add(19)(p13.3)[20]

FISH:

-MLL gene: rearranged

-ETV gene: deleted

-PML/RARA: negative

-BCR/ABL: negative

- t(4;11)(q21;q23)MLL-AF4 detected by nanofluidics PCR

- FLT3: wild-type

- PML/RARA: wild-type

- RUNX1/RUNX1T1: wild-type

- CBFβ/MYH11: wild-type

- BCR/ABL: wild-type

MLL gene rearrangement with MLLT2 (AF4) as a partner is common in acute lymphoblastic leukemia, but rare (1.7%)* in acute myeloid leukemia. t(4;11) in pediatric acute myeloid leukemia is not an independent prognostic factor*. t(2;4;11) is a rare variant of MLL gene rearrangement, confirmed by PCR, in acute myeloid leukemia.

*Blood 2009;114:2489-96

Acute myeloid leukemia with MLL gene rearrangement

Acute myeloid leukemia with (variant) t(4;11)(q21;q23); MLLT2-MLL (AF4-MLL)

Case 84