[Large granular lymphocytic leukaemia].

BACKGROUND Large granular lymphocytic leukaemia (LGL-leukaemia) is considered a rare disease. LGL-leukaemia is usually of the T-cell type, but a minority displays an NK-cell phenotype. Incidence and prevalence are unknown. MATERIAL AND METHODS We identified patients with LGL-leukaemia (with well-defined diagnostic criteria) diagnosed at Rikshospitalet University Hospital between 01.10.2001 and 31.12.2007. Their medical records were assessed retrospectively. RESULTS LGL-leukaemia was diagnosed in 52 patients, 26 women and 26 men, median age of 59 (26 - 86) years, during the study period. The leukaemia displayed NK-cell phenotype in one patient and T-cell phenotype in the remaining 51 patients. Slightly more than one third of the patients were asymptomatic. Cytopenia, mostly neutropenia, was usually the cause of the clinical phenotype in symptomatic patients. Co-morbidity with autoimmune disease was common, and we also found a high prevalence of clonal B-cell disease (17 %). INTERPRETATION Our data support the notion that LGL-leukaemia is under-diagnosed. Unexplained cytopenias should suggest the possibility of LGL-leukaemia, and appropriate diagnostic measures should be undertaken. An early diagnosis may save patients an extensive and unnecessary diagnostic work-up and ensure that a simple and effective treatment is offered.