Hepatosplenic T-cell lymphoma diagnosed using flow cytometry. A single-center study of 12 cases from North India.

<bold>Background: </bold>Hepatosplenic T-cell lymphoma (HSTCL) is a rare fatal T-cell neoplasm with unique clinical and laboratory features. There is, however, significant morphological and immunophenotypic heterogeneity which may lead to diagnostic dilemma.<bold>Aims and Objectives: </bold>The study was aimed to study the prevalence and clinic-pathological spectrum of this rare variant of T cell lymphoma in the Indian subcontinent.<bold>Material and Methods: </bold>A retrospective analysis of all consecutive cases of HSTCL diagnosed over a period of 6 years was carried out. The clinical and laboratory parameters of all these patient were reviewed and analysed.<bold>Results: </bold>A total of 12 cases of HSTCL were diagnosed during this period which accounted for 1.76% of all non-Hodgkin's lymphomas (NHLs) and 9.1% of all T-cell NHLs. The median (range) age of presentation was 23 (16-30) years.Leukocytosis, peripheral blood (PB) involvement, and a blastic morphology were noted in 41%, 67%, and 58% of the cases, respectively. FCI proved these cells to have a mature, dual-negative (CD4-/CD8-) T-cell phenotype with a gamma-delta T-cell receptor restriction. Frequent loss of CD5 expression (84%) was also noted. These patients invariably had a fatal outcome and majority died within a year of diagnosis.<bold>Conclusion: </bold>The incidence of leukocytosis and a blastoid morphology is quite frequent in HSTCL. Hence, a differential diagnosis of HSTCL should always be considered in young patients presenting with splenomegaly and exhibiting atypical lymphoid/blastoid cells in the PB or a marrow. An FCI can readily diagnose and differentiate them from an acute lymphoblastic leukemia/lymphoma. [ABSTRACT FROM AUTHOR]