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Giant parallel tubular arrays in T lymphocytes

Giant parallel tubular arrays in T lymphocytes
#00015907
Author: David M. Ross and John Stirling
Category: Lymphoma: Mature T and NK cell lymphoproliferations > Mature T-cell Leukemias > T-cell Large Granular Lymphocytic Leukemia
Published Date: 01/17/2013

A 77-year-old man with seropositive rheumatoid arthritis was investigated for mild pancytopenia. He had mild splenomegaly, but no adenopathy. Hemoglobin was 117 g/L, platelets 126 × 109/L, and leukocytes 2.0 × 109/L with 96% lymphocytes, most of which were large granular lymphocytes (LGLs). Immunophenotyping showed an aberrant T-cell population co-expressing CD3, CD8, and CD57 with reduced expression of CD5, and absent CD56. T-cell receptor gene rearrangement confirmed a monoclonal T-cell population, consistent with T-LGL leukemia. After treatment with methotrexate lymphocytosis and splenomegaly resolved, but cytoplasmic inclusions remained. Approximately 40% of lymphocytes contained cytoplasmic inclusions, either single or multiple, and in some cells the inclusions were associated with a cytoplasmic vacuole (see figure). The inclusions had a color resembling that of nuclear chromatin, with variable shapes ranging from round to rod-like. Electron microscopy showed them as giant paralle