Splenic marginal zone lymphoma presenting as myelofibrosis associated with bone marrow involvement of lymphoma cells which secrete a large amount of TGF-β

We report here on a patient with splenic marginal zone lymphoma presenting diffuse fibrosis of bone marrow and spleen. After splenectomy and chemotherapy, bone marrow biopsy demonstrated an improvement of fibrosis. Plasma concentration of transforming growth factor (TGF)-β was much higher in this patient than in those of age-matched non-Hodgkin's lymphoma patients (n=5) at diagnosis, decreasing after resolution of myelofibrosis. Immunostaining with the TGF-β antibody revealed that the lymphoma cells in bone marrow and spleen were positive for TGF-β. TGF-β secreted by tumor cells was thought to stimulate the growth of fibroblasts and synthesize collagen in bone marrow and splenic fibroblasts, and play an important role in the development of marrow and splenic fibrosis in this patient. This is the first report of a patient with splenic marginal zone lymphoma presenting as myelofibrosis associated with bone marrow involvement of lymphoma cells which secrete a large amount of TGF-β.