LAUSR

T‐cell prolymphocytic leukemia (T‐PLL) is a rare, post‐thymic T‐cell neoplasm with a diverse clinical course. T‐PLL is typically associated with a poor prognosis; however, a subset of patients have inactive disease on initial presentation. There is a lack of accurate delineation of the disease based on initial clinical presentation and pathological assessment, hindering clinical decision‐making. To characterize and delineate disease subtypes based on initial clinical presentation and pathologic assessment, we retrospectively reviewed 81 patients with T‐PLL treated at our institution. We compared patients with T‐PLL who initially presented with a relatively indolent or stable disease course to those with an aggressive disease course. Clinicopathologic characteristics, overall survival (OS), and prognostic factors were analyzed. Patients with inactive disease had a significantly longer OS than patients with active disease. At diagnosis, presence of B symptoms, low hemoglobin, low platelet count, lymphocyte doubling time of fewer than 3 months, and abnormal cytogenetics were associated with shorter OS. Cell morphology, immunophenotype, absolute lymphocyte count, lactate dehydrogenase levels, involvement of liver, spleen, skin or central nervous system, presence of TCL1 rearrangement or inv (14)/t(14;14), presence of chromosome 8 abnormalities, and presence of deletion of 11q were not associated with significant OS difference among the patients. Receiving alemtuzumab as first‐line treatment and consolidation with allogeneic hematopoietic stem cell transplant were associated with better outcomes. T‐PLL inactive and active disease subtypes can exhibit overlapping yet different clinical and pathological features. We describe several prognostic factors at diagnosis that can be used for risk stratification and aid in guiding treatment decisions.