The spectrum of T-cell and natural killer/T-cell neoplasms with leukaemic presentation in a single institution in Taiwan

T cell and natural killer (NK)/T-cell neoplasms are rare and may occasionally present as leukaemia. We retrospectively searched T cell and NK/T-cell tumours in a single institution in Taiwan from January 2000 to December 2009 and identified 137 (19.1%) patients with T cell and NK/T-cell tumours among 718 patients with lymphoid neoplasms. Among these 137 patients, 18 (13.1%) presented with leukaemia including T-lymphoblastic lymphoma/leukaemia (T-LBL), T-cell prolymphocytic leukaemia, aggressive NK-cell leukaemia, adult T-cell lymphoma/leukaemia (ATLL), T-cell large granular lymphocytic (T-LGL) leukaemia and unspecified peripheral T-cell lymphoma. Cases with concurrent lymphoma, higher absolute leukaemic cell counts and elevated lactate dehydrogenase level carried a poorer prognosis. The survival was dichotomous, with a very poor prognosis for patients with T-LBL, T-cell prolymphocytic leukaemia, aggressive NK-cell leukaemia, ATLL in acute phase and unspecified peripheral T-cell lymphoma, while those with T-LGL leukaemia and ATLL in chronic phase had a favourable outcome.