Secondary bone marrow involvement of non-Hodgkin's lymphoma (NHL) is relatively common. However, primary isolated bone marrow involvement in NHL which was successfully treated and remains in complete remission (CR) for a long-term duration without any relapse is extremely rare. We herein report a patient of primary bone marrow diffuse large B cell lymphoma (PBML/DLBCL) who presented a prolonged high-grade fever and systemic purpura due to severe thrombocytopenia. The patient was successfully treated with systemic chemotherapy by R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisolone) and remains in CR at 8 years after the initial diagnosis. Review of the literature in PBML/DLBCL cases are also shown.