T-cell Prolymphocytic Leukemia



T-cell Prolymphocytic Leukemia


Kathryn Foucar, MD









This peripheral blood smear shows a striking leukocytosis, which exceeded 530 × 109/L in this elderly woman. Hemoglobin was preserved while platelets were mildly decreased in this case of T-cell prolymphocytic leukemia.






The leukocytes in this case of T-prolymphocytic leukemia show very distinctive nuclear and cytoplasmic features. Note the nuclear irregularity and cytoplasmic blebbing.


TERMINOLOGY


Abbreviations



  • T-cell prolymphocytic leukemia (T-PLL)


Synonyms



  • T-cell chronic lymphocytic leukemia


Definitions



  • Mature T-cell leukemia composed of small to medium-sized lymphocytes



    • Variably prominent nucleoli


    • Variable nuclear irregularity


    • Scant to moderate amounts of cytoplasm


  • Recurrent cytogenetic finding: inv(14)(q11q32)


ETIOLOGY/PATHOGENESIS


Leukemogenesis



  • Key leukemogenic role of TCL1 oncoprotein overexpression


  • Translocations of TCL1 gene(s) into promoter/enhancer regions of TCRα/δ dysregulates TCL1


  • ATM deletions and haploinsufficiency of CDKN1B also leukemogenic


CLINICAL ISSUES


Epidemiology



  • Incidence



    • 2% of chronic leukemias in adults


    • Increased incidence in patients with ataxia telangiectasia


    • No association with environmental exposure


    • No link to infections established


  • Age



    • Median: 65 years (range: 30-90 years)


  • Gender



    • Male predominance (3:1)


  • Ethnicity



    • No key ethnic associations


Site



  • Blood, bone marrow, spleen, liver, lymph nodes


  • Less often skin, effusions


Presentation



  • 90% of patients symptomatic


  • Key symptoms include abdominal distension, bulky lymph nodes, skin rash


  • Marked splenomegaly and hepatomegaly typical


  • Skin lesions and pleural effusions in subset


Laboratory Tests



  • Key laboratory tests include CBC with differential, flow cytometric immunophenotyping, and conventional cytogenetics


  • CBC shows marked lymphocytosis (WBC > 100 × 109/L in 50% of cases)


  • Additional CBC findings include anemia (25%) and thrombocytopenia (50%)


Natural History



  • Aggressive disease; 20% overall 5-year survival rate


  • Better outcome for responders to CAMPATH-1H


Treatment



  • Drugs



    • Various agents used, including purine analogs


    • Best results achieved with humanized monoclonal antibody alemtuzumab (anti-CD52) (CAMPATH-1H)


    • Newer treatments include



      • Other monoclonal antibody agents


      • Nonmyeloablative stem cell transplant


      • Radioimmunotherapy


Prognosis



  • Poor; median survival of non-CAMPATH-1H responders is 4 months



  • Overall median survival is about 2 years


  • 20% 5-year survival

Jun 13, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on T-cell Prolymphocytic Leukemia
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