Submitting Author: Chen, Dong, MD,PhD
Institution: Mayo Clinic
Additional authors:James D. Hoyer, MD
Session: Erythroleukemia and megakaryoblastic AML and mimics

81 year old man was found to have anemia and thrombocytopenia in 2008.

In October 2009, his hemoglobin was 10.5, MCV 95.1, white count 1.9 with 24% neutrophils, and platelet count 45,000. Peripheral smear revealed a leukoerythroblastic picture. A bone marrow biopsy was consistent with refractory cytopenia with multilineage dysplasia with 1% blasts. He was then observed for one year.

In 2010, He became transfusion dependent, and was treated with a total of 3 cycles of decitabine.

In 2011, a follow up bone marrow biopsy was formed (the submitted case).

Patient died 2 months later at the age of 84.

Tissue Description:

A. Bone Marrow Aspirate:

B. Bone Marrow Biopsy: The bone marrow core biopsy consists of 2 pieces of tissue having an aggregate length of 2.3 cm, fixed in B5 and formalin and decalcified. All embedded.

C. PBSM Peripheral Blood Smear

Microscopic Description:

Peripheral Blood

CBC (dated 9/6/11): Hgb 8.3 g/dL; RBC 2.77 x 10(12)/L; MCV 87.7 fL; RDW 14.0%; WBC 0.5 x 10(9)/L; PLT 39 x 10(9)/L.

White blood cell differential %: neutrophils 5; lymphocytes 75; eosinophils 15; blasts 5.

Peripheral smear: Marked pancytopenia.

Red blood cells: Morphologically unremarkable. Absent adequate polychromasia.

White blood cells: Rare normal-appearing neutrophils; 5% circulating blasts with high N:C ratio, open chromatin and scant cytoplasm, no Auer rods seen.

Platelets: Morphologically unremarkable.

Bone Marrow Aspirate/Touch Imprint

Bone marrow differential (500-cell/unit prep): neutrophils (segs and bands) 3; metamyelocytes 1; myelocytes 3; promyelocytes 2; eosinophils and precursors 4; blasts 9; normoblasts 60; monocytes 2; lymphocytes 14; plasma cells 2.

Quality: Markedly hypercellular; estimated M:E ratio 1:3.

Erythroid precursors: Markedly increased, approximately 60% of total mononuclear cells in bone marrow; megaloblastoid differentiation; overt dyserythropoietic features, including cytoplasmic vacuolization, nuclear blebbing, bridging, mitosis and karyorrhexis.

Granulocytic precursors: Markedly decreased; left-shifted maturation; occasional hypogranular forms present; 9% blasts with similar morphologic features as in the peripheral blood.

Megakaryocytes: Slightly increased; numerous small, hypolobated and osteoclast-like forms.

Lymphocytes and plasma cells: Not increased and cytologically unremarkable.

Bone Marrow Biopsy/Clot

Quality: Adequate.

Cellularity: Markedly hypercellular for age, 90%.

Erythroid precursors: Markedly increased; marked left-shifted maturation, approximately 60-70% of the bone marrow cellularity.

Granulocytic precursors: Markedly decreased; left-shifted maturation; no obvious foci or sheets of blasts.

Megakaryocytes: Slightly increased; frequent small, monolobate and osteoclast-like forms.

Lymphocytes: No lymphoid aggregates or infiltration by cytologically atypical lymphocytes seen.

Plasma cells: Not increased and cytologically unremarkable.

Iron stain, bone marrow aspirate: Markedly increased iron storage. Sideroblasts present; absent ring sideroblasts.

Immunohistochemical studies, bone marrow biopsy, antibodies to CD34, CD61, hemoglobin, glycophorin A: There are about 10% CD34-positive blasts. CD61 highlights numerous small, atypical megakaryocytes. Most of the mononuclear cells are erythroid precursors (60%) which are highlighted by either hemoglobin or glycophorin A immunostains. Some erythroid precursors also coexpress CD34.

47,XY,-7,+19,+21[20]

The patient’s bone marrow had about 10% myeloblasts and 60% left-shifted normoblasts. The case could be classified as either RAEB-2 or acute erythroid leukemia (AML-M6) with myelodysplastic related changes (MRC).

1: Liu W, Hasserjian RP, Hu Y, Zhang L, Miranda RN, Medeiros LJ, Wang SA. Pure erythroid leukemia: a reassessment of the entity using the 2008 World Health Organization classification. Mod Pathol. 2011 Mar;24(3):375-83.

2: Hasserjian RP, Zuo Z, Garcia C, Tang G, Kasyan A, Luthra R, Abruzzo LV,Kantarjian HM, Medeiros LJ, Wang SA. Acute erythroid leukemia: a reassessment using criteria refined in the 2008 WHO classification. Blood. 2010 Mar 11;115(10):1985-92.

Acute erythroid leukemia (AML-M6) with myelodysplasia-related changes (MRC)

Progression of myelodysplastic syndrome to erythroid predominant myeloid neoplasm:

Acute erythroid leukemia, erythroid/myeloid type (WHO classification) versus refractory anemia with excess blasts-2, RAEB-2

Case 71