Laboratory findings The requisite lymphocytosis of this disease is typically 2-20x109/L. Immunoglobulin derangements including hypergammaglobulinemia, autoantibodies, and circulating immune complexes are commonly seen. Peripheral blood The neoplastic lymphocytes seen in this disease are<unk>  in size with azurophilic granules that contains proteins involved in cell lysis such as perforin and granzyme B. Flow cytometry is also commonly used. Bone marrow Bone marrow involvement in this disease is often present, but to a variable extent. Bone marrow biopsy is commonly used for diagnosis. The<unk>  infiltrate is usually interstitial, but a nodular pattern rarely occurs. Immunophenotype The neoplastic cells of this disease display a mature T-cell immunophenotype, with the majority of cases showing a CD4-/CD8+ T-cell subset immunophenotype versus other permutations of those markers. Variable expression of CD11b, CD56, and CD57 are observed. Immunohistochemistry for perforin, TIA-1, and granzyme B are usually positive. Type Immunophenotype Common type (80% of cases) CD3+, TCRαβ+, CD4-, CD8+ Rare variants CD3+, TCRαβ+, CD4+, CD8- CD3+, TCRαβ+, CD4+, CD8+ CD3+, TCRγδ+, CD4 and CD8 variable Genetic findings Clonal rearrangements of the T-cell receptor (TCR) genes are a necessary condition for the diagnosis of this disease. The gene for the β chain of the TCR is found to be rearranged more often than the γ chain. of the TCR. Current evidence suggests that patients with STAT3 mutations are more likely to respond to methotrexate therapy.
Large granular lymphocytic leukemia
Hemophagocytic lymphohistiocytosis
Aggressive NK-cell leukemia
Mixed-phenotype acute leukemia
T-lymphoblastic leukemia/lymphoma
Atypical chronic myeloid leukemia
Diffuse infiltrative lymphocytosis syndrome
Adult T-cell leukemia/lymphoma