Algorithm for classification of T-cell neoplasms involving peripheral blood. Cases were classified by sequential application of the most prominent presenting feature, beginning with adult T-cell leukemia-lymphoma (ATLL, excluded from study), T-cell prolymphocytic leukemia (T-PLL), primary or secondary Sezary syndrome (SS), T-cell large granular lymphocyte (T-LGL) leukemia, and hepatosplenic T-cell lymphoma (HSTCL). Nodal peripheral T-cell lymphoma (PTCL) and angioimmunoblastic T-cell lymphoma (AIL) involving peripheral blood (PB) were not included in this analysis.