Distinguishing hairy cell leukemia variant from hairy cell leukemia: development and validation of diagnostic criteria.
Hairy cell leukemia (HCL) and hairy cell leukemia-variant (HCL-v) are rare diseases with overlapping clinico-pathological features. We performed flow cytometry analysis (FCM) of 213 cases (169 HCL, 35 HCL-v, 9 splenic marginal zone lymphoma (SMZL)), correlating results with available corresponding clinical and morphological data. FCM distinguished HCL-v from HCL and SMZL based solely upon expression of four antigens (CD11c, CD25, CD103, CD123) combined with B-cell markers (CD19, CD20, CD22). HCL-v expressed bright CD20, bright CD22, CD11c(100%), CD103(100%), dim(40%) or negative(60%) CD123, and uniformly lacked CD25(100%). HCL expressed bright CD20, bright CD22, bright CD11c, bright CD25, CD103, and bright homogeneous CD123(100%). Aberrant expression of CD5(2%/3%), CD10(12%/3%), CD23(21%/11%), CD38(14%/0%), CD2(2%/9%), CD4(0.5%/0%) and CD13(0.5%/3%), was observed in HCL/HCL-v, respectively. SMZL cases were CD103(-) and CD123(-) except for one case with dim CD123. HCL showed significantly greater marrow infiltration over HCL-v. Prominent nucleoli were observed in most HCL-v but rarely in HCL. A third of HCL and HCL-v marrows were hypocellular or aplastic-appearing. Detection of BRAFV600E mutation and annexin A1 were examined in a subset of cases to further validate FCM diagnostic criteria. HCL-v was negative for both annexin A1 (100%) and BRAFV600E mutation (100%), in contrast to HCL (74% positive for annexin A1; 76% positive for BRAFV600E mutation). HCL-v is resistant to traditional HCL therapy, making accurate diagnosis imperative. We have defined FCM criteria for differentiation of HCL-v from HCL and SMZL.
Hematopathology and Laboratory Medicine, H Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA.
Haipeng
H
Shao
Hematology Section, Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, MD, USA.
Katherine R
KR
Calvo
Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
Marlene
M
Grönborg
Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
Prashant R
PR
Tembhare
Laboratories of Molecular Biology and Clinical Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
Robert J
RJ
Kreitman
Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
Maryalice
M
Stetler-Stevenson
Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA. Electronic address: yuanc@mail.nih.gov.
Constance M
CM
Yuan
D003937:Diagnosis, Differential; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D007943:Leukemia, Hairy Cell / Q000175:diagnosis / Q000473:pathology*