We report an unusual case of the 'reverse' variant of follicular lymphoma in which the nodules had central parts that stained dark and cuffs that stained pale. Because diagnosis was difficult relying only on formalin-fixed histopathology, we examined the cell surface markers and karyotype. The patient, a 65-year-old man, presented with multiple lymphadenopathy, low-grade fever, night sweats, anorexia, dry cough and sense of chest oppression. Cell surface marker analysis showed that pathologic lymphocytes were positive for CD 10, CD 19, CD 20, HLA-DR, IgM/IgD and kappa, and t (14; 18) (q 32; q 21) was detected by karyotypic analysis. The 'reverse' variant of follicular lymphoma, clinical stage IVB was diagnosed the rearrangement band was detected with PCR-based clonality analysis in not only the immunoglobulin heavy chain gene but also the T cell receptor gamma chain gene, thus confirming monoclonal proliferation of both B cells and T cells.