Document Type

Poster

Study Type

Case Report

Publication Date

9-1-2017

Journal

Archives of Pathology & Laboratory Medicine

Volume

141

Issue

9

Inclusive Pages

e2-e191

Keywords

Acute Myelomonocytic Leukemia, Acute Promyelocytic Leukemia, Tetrasomy 8

Abstract

Rare cases of acute myeloid leukemia (AML) with tetrasomy 8 have been reported. Tetrasomy 8, a poor prognostic factor, has been predominantly associated with AML with monocytic differentiation. We report an unusual case of acute myelomonocytic leukemia (AMML) with tetrasomy 8 showing histologic and immunophenotypic features mimicking acute promyelocytic leukemia (APL). The patient is a 63-year-old African American man with molar pain, gum swelling and bleeding, generalized fatigue, leukocytosis, anemia, and thrombocytopenia. A peripheral blood smear showed increased white cells with many immature granulocytic forms. Approximately 40% of the cells exhibited classical blast morphology, 40% were slightly enlarged and exhibited a small to moderate amount of cytoplasm with a variable number of cytoplasmic granules resembling atypical promyelocytes, and 10% exhibited morphology typical of promyelocytes. The presence of promyelocytes and atypical promyelocytes was highly suggestive of APL. Flow cytometry performed on the peripheral blood showed the leukemic cells to express CD11b (subset), CD33, CD56, and CD64 (subset), with no expression of HLA-DR or CD34, suggestive of APL; however, the blasts were negative for CD117. Subsequent bone marrow aspirate/biopsy evaluation was consistent with AMML. FISH analysis showed tetrasomy 8 and absence of PML/RARA gene rearrangement. In this case, AMML with tetrasomy 8 morphologically and immunophenotypically mimicked APL. The treatment and prognosis of these subtypes of AML are significantly different. This case illustrates the importance of cytogenetic analysis and thorough bone marrow evaluation in determining accurate diagnosis of AML.

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