Case 412

Submitting Author: Raza, Adeel M, MD
Institution: The Methodist Hospital, Texas Medical Center
Additional authors:April Ewton, MD
Session: Erythroleukemia and megakaryoblastic AML and mimics

HISTORY

66 year old female diagnosed with myelodysplastic syndrome (MDS) in 2010. She received azacitidine and decitabine at that time. Bone marrow biopsy done in June 2012 showed progression in MDS. Her medications changed to lenalidomide and azacitidine. She again underwent bone marrow biopsy in July, 2012

DETAILS

Bone marrow biopsy, aspirate and peripheral blood: Peripheral blood revealed normocytic anemia with basophilic stippling. There was marked leukocytopenia with occasional hypogranulation of neutrophils and rare blasts. Platelets were markedly decreased with normal morphology. The marrow cellularity was approximately 100 % predominantly consisted of erythyroid colonies accounting for approximately 60% of bone marrow cellularity. (figure1) There were scattered blasts (7.5%). M:E ratio was 1:4. Bone marrow aspirates revealed erythroid hyperplasia with moderate dysplasia (megaloblastic changes, nuclear irregularity and multinucleation) (figure 2). Prussian Blue stain on aspirate showed ringed sideroblasts (~30% of erythroid precursors) (figure3). Myeloids were decreased in number with left shift in maturation and increased blasts (7.5%). There was hypogranulation and hypolobation of the neutrophils. Megakaryocytes were decreased in number with micromegakaryocytic forms. (figure4)

IMMUNOHISTOCHEMISTRY AND FLOW CYTOMETRY

Results of immunohistochemical stains: Hemoglobin A shows marked erythroid hyperplasia (figure5). E-cadherin highlights clusters and sheets of immature erythroids (figure6). CD34 and CD117 highlightd scattered blasts. Flow cytometry detected 5-7% myeloblasts with subsets expressing CD56 and CD7.

CYTOGENETIC FINDINGS

46,XX, -7[20]

MOLECULAR FINDINGS

N/A

INTERESTING FEATURES

The case describes an example of MDS- related acute myeloid leukemia arising from MDS. Interesting features include AML NOS, Acute Erythroleukemia (erythroid/myeloid ), the presence of the ring sideroblasts and rapid disease transformation.

PROPOSED DIAGNOSIS

Acute myeloid leukemia with myelodysplasia related changes (AML-MRC) with morphologic features of Acute erythroid leukemia (erythroid/myeloid)

CONSENSUS DIAGNOSIS

Progression of myelodysplastic syndrome to erythroid predominant myeloid neoplasm (7-8% blasts):
Acute erythroid leukemia, erythroid/myeloid (WHO classification) versus refractory anemia with excess blasts-2, RAEB-2