Onset of oral extranodal large B-cell non-Hodgkin's lymphoma in a patient with polycythemia vera: a rare presentation.

Polycythemia vera (PV) is a hematologic malignancy characterized by excessive proliferation of erythroid, myeloid and megakaryocytic elements in the bone marrow. Patients suffering from PV may subsequently be affected by other neoplasms of the haematopoietic system, but lymphomas are very rare and no cases of oral lymphoma have yet been reported. We report the case of a patient with PV in whom a primary non-Hodgkin's lymphoma (high grade malignancy on the Kiel scale) of the oral cavity subsequently developed. The case is unusual for its extranodal onset, its location in the oral cavity and the clinical presentation.