We managed a peculiar case of lymphoma showing immunohistochemical overexpression of cyclin D1. At initial examination the patient had meningeal lymphomatosis and general lymphadenopathy. Histologic examination of biopsy specimens of inguinal lymph nodes showed tumor cells and vague nodular growth resembling lymphoblasts. The results of flow cytometric analysis were positive for CD10, CD20, CD103, and immunoglobulin G (IgG) and Ig kappa and were negative for CD5, CD23, and terminal deoxynucleotidyl transferase activity. Results of immunohistochemical analysis of paraffin-embedded specimens were positive for cyclin D1 and Bcl2 in the tumor cells. Sixty percent of tumor cells had positive results for MIB1/Ki67. Cytogenetic and molecular studies revealed tumor cells simultaneously had t(14;18)(q32;q21), t(11;22)(q13;q11), t(8;14)(q24;q32), and t(3;14)(q27;q32) with the rearrangement of BCL1, BCL2, BCL6, and c-MYC genes. Lymphadenopathy showed a quick and complete response to doxorubicin-containing systemic chemotherapy with rituximab, but the central nervous system disease progressed and killed the patient.