Diffuse large B-cell lymphoma and polycythemia vera discovered at the onset - a rare association and its possible importance in lymphoma prognosis.

Unlabelled: Diffuse large B-cell lymphoma (DLBCL) represent the most frequently non-Hodgkin's lymphoma (NHL) (over 30%), especially in developing countries. Many associations of NHL with another neoplasia were described following chemotherapy or radiotherapy regimens. The coexistence of DLBCL with myeloproliferative neoplasms (MPNs) JAK2V617F positive at the onset was very rare reported in the literature. We describe a clinical case of a 52-year-old man who presented both diagnoses at the onset - DLBCL and MPN - polycythemia vera (PV) type. The patient was treated with two CHOP cycles (Cyclophosphamide, Hydroxydaunorubicin, Oncovin, Prednisolone) followed by six R-CHOP (Rituximab-CHOP) cycles, together with a platelet-reducing agent, achieving remission for 20 months, followed by a relapse which is under treatment. The clonally expansion of an abnormal pluripotent hematopoetic stem cell could be responsible for both, PV and DLBCL. However, recent reports suggested the possible involvement of two different clones. The clinical significance and the role of JAK2 mutation in the evolution of patients with NHLs, including DLBCL are still unknown. Further genetic and clinical studies have to point out common gene mutations for the two diseases and their connection with the diseases behavior under the treatment.

Conclusions: The coexistence of NHLs and especially DLBCLs and MPNs JAK2 positive is very rare. Although DLBCL alone has good prognosis, other prognostic factors should be checked when it is associated with PV. The presence of JAK2V617F seems to be a candidate but whose role in DLBCL evolution, natural or under treatment has to be cleared up.