Acute promyelocytic leukemia, hypogranular variant, with uncharacteristic staining with chloroacetate esterase.
A diagnosis of the hypogranular variant of acute promyelocytic leukemia (APLv) may be difficult to establish based on cytomorphology alone. However, the great majority of cases have a classical immunophenotype by flow cytometric immunophenotyping (FCI) (CD13+, CD33+, dim CD64+, HLA-DR-, and CD34-) and a classical enzyme cytochemical (EC) staining pattern. [intensely staining with myeloperoxidase, Sudan Black B, and chloroacetate esterase (CAE) and negative with alpha'-naphthyl acetate and butyrate esterases]. Although the immunophenotype of APLv by FCI has varied in the literature (HLA-DR +/- and CD34 +/-), the EC staining pattern has remained constant. We report a case of APLv with characteristic cytomorphology, compatible FCI data (CD13+, CD33+, dim CD64+, HLA-DR +/-, and CD34-), chromosomal detection of t(15; 17), and molecular detection of the PML/RAR alpha fusion gene; however, staining of the leukemic cells with CAE was quite uncharacteristic. We describe our findings.
Dunphy
C H
CH
Division of Hematopathology, Department of Pathology, St. Louis University Health Sciences Center, St. Louis, Missouri, MO 63014, USA. dunphyc@slucare1.sluh.edu
Polski
J M
JM
Johns
G
G
Evans
H L
HL
Gardner
L J
LJ
D000368:Aged; D002265:Carboxylic Ester Hydrolases / Q000032:analysis*; D002884:Chromosomes, Human, Pair 15; D002886:Chromosomes, Human, Pair 17; D020732:Cytogenetic Analysis; D006651:Histocytochemistry; D006801:Humans; D016130:Immunophenotyping; D015473:Leukemia, Promyelocytic, Acute / Q000175:diagnosis / Q000201:enzymology / Q000473:pathology*; D008297:Male; D013194:Staining and Labeling; D014178:Translocation, Genetic
D002265:Carboxylic Ester Hydrolases; C019873:chloroacetate esterase