Abstract
The coexistence of both myeloproliferative and lymphoproliferative neoplasms in the same patient is an uncommon finding. We report two patients who presented such an association. The first patient was initially diagnosed with essential thrombocythemia, developing a clinical and haematological picture consistent with chronic lymphocytic leukaemia several years afterwards. The second patient was diagnosed concomitantly with polycythaemia vera and chronic lymphocytic leukaemia. Both patients were positive for the JAK2 V617F mutation. In the first patient the chronic lymphocytic leukaemia was asymptomatic, stage A, and did not require any additional treatment, while the second patient presented with generalized large lymphadenopathy (stage B) and chronic lymphocytic leukaemia-related symptoms, requiring chronic lymphocytic leukaemia-directed treatment. It is unclear whether there is a pathogenetic link between the myeloproliferative and lymphoproliferative diseases encountered in these patients, both being probably the result of random mutations occurring in distinct initiating cells. However, given the higher risk of lymphoproliferative neoplasms development in myeloproliferative neoplasms patients reported in larger studies, the genomic instability characteristic to myeloproliferative neoplasms may play a role in subsequent lymphoproliferative neoplasms occurrence.