Most common T cell lymphoma category in non-EBV-endemic populations (North America/Europe)
Predominantly nodal presentation
Extranodal involvement common
skin, gastrointestinal tract, liver, bone marrow
Generally aggressive lymphomas with poor response to therapy
Category likely comprises heterogeneous clinical entities which cannot be reliably distinguished
Morphologic categories not prognostically useful
Cytotoxic marker (granzyme and/or TIA-1) positivity has been proposed as a poor prognostic factor in a Japanese study; however the poor outcome could also have been due to concomitant EBV positivity, and it is not clear whether this is true in non-EBV endemic populations
