AUTHOR=Nagy Zsófia F., Ferenczi Kata, Istenes Ildikó, Eid Hanna, Bödör Csaba, Timár Botond, Demeter Judit TITLE=Case Report: Development of Diffuse Large B Cell Lymphoma a Long Time After Hairy Cell Leukemia JOURNAL=Pathology and Oncology Research VOLUME=28 YEAR=2022 URL=https://www.por-journal.com/articles/10.3389/pore.2022.1610338 DOI=10.3389/pore.2022.1610338 ISSN=1532-2807 ABSTRACT=Hairy cell leukaemia (HCL) is a rare B cell malignancy with an indolent course leading to pancytopaenia due to bone marrow infiltration. It has been proposed that HCL patients are at risk of developing a secondary malignancy, with a marked likelihood of the development of other hematologic malignancies including Hodgkin lymphoma and high-grade non-Hodgkin lymphomas. Here, we present the case of two patients who developed diffuse large B cell lymphoma after a long course of hairy cell leukaemia. In the case of the female patient, we report on the occurrence of a third malignant disease, which is very uncommon. With our case descriptions we contribute to the very small number of similar cases reported.