[1470] The Pathologist's Approach to T-Cell Large Granular Lymphocytic Leukemia Diagnosis: A Multicenter Comparative Study by the Bone Marrow Pathology Group

Jadee L Neff, Xiangshan Fan, Robert Ohgami, Yue Wu, Sarah M Choi, Rebecca L King, Damian J Tagliente, Adam Bagg, Attilio Orazi, Daniel A Arber, Sa A Wang, William G Morice II. Mayo Clinic, Rochester, MN; Stanford School of Medicine, Stanford, CA; University of Pennsylvania Perelman School of Medicine, Philadelphia, PA; Weill Cornell Medical College, New York, NY; MD Anderson Cancer Center, Houston, TX

Background: Clinically, T-cell large granular lymphocytic leukemia (T-LGL) is diagnosed by documentation of an increase in peripheral blood (PB) large granular lymphocytes in the setting of unexplained cytopenia. A number of pathologic studies can be used to establish T-LGL, including flow cytometric (FC) T-cell phenotyping, bone marrow (BM) biopsy and immunohistochemistry (IHC), and T-cell clonality assessment. The expected findings from these studies in T-LGL are described in the WHO Classification scheme; however, the frequency with which they are employed in routine case evaluation is unknown. To address this, data from 5 major academic medical centers was compared.
Design: Clinical and laboratory data from 201 T-LGL cases identified in the files of 5 major academic medical centers were compared.
Results: The CBC and clinical data in Table 1 match those expected of T-LGL; treatment was required in 49%. An associated non-T-LGL hematologic disorder was present in 28%, an autoimmune disorder in 22%.

CBC and Clinical Data from T-LGL Cases
Median Age, (y)60
Male:Female120:81
% Hemoglobin<10.0 g/dL26%
%ANC<1.5 x 10(9)/L60%
%Platelet<100 x 10(9)/L13%
%Abs GL Count>2.5 x 10(9)/L58%
%Splenomegaly16%
ANC=Absolute neutrophil count. GL=Granular lymphocyte

Table 2 shows the frequency with which the various studies were performed in the T-LGL cases. FC was performed more often on BM than PB (127 vs. 72). BM IHC for CD3 and CD8 was performed on the majority, IHC for cytotoxic granule proteins was less frequent (39%). T-cell clonality molecular studies were not performed in 19 cases, in 8 of these cases T-cell clonality was assessed by V-beta FC.

How Often are Various Studies Performed for T-LGL Diagnosis?
% Flow Cytometry99%
% BM Biopsy85%
% BM IHC60%
% T-cell gene rearrangement90%
BM=bone marrow


Conclusions: This study found a consistent, comprehensive laboratory approach to T-LGL evaluation between medical centers. While the extent of the studies performed may be biased by the academic practice setting, this data provides a context to determine the minimal elements requisite for diagnosis and the formulation of universally applicable best practice recommendations.
Category: Hematopathology

Tuesday, March 5, 2013 2:30 PM

Proffered Papers: Section G, Tuesday Afternoon

 

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