抄録
Downgrading of non-Hodgkin's lymphoma is a rare event. In this paper, we report 3 cases of diffuse large B-cell lymphoma (DLBL) which relapsed as low-grade follicular center lymphoma (FCL). Patient 1 showed complete remission following chemotherapy, but relapsed into FCL 7 years later. This patient developed DLBL again after spontaneous apparent disappearance of FCL. Patients 2 and 3 had a relapse of FCL 7 and 3 years after the therapy for the initial DLBL, respectively. Clonal immunoglobulin heavy chain rearrangement was analyzed by the polymerase chain reaction (PCR) and sequencing of the PCR products. The PCR products at presentation and at relapse in Patient 3 were different in size. The size of the PCR products in Patient 1 was almost the same at presentation and at relapses, but their CDR3 sequences were all different. The PCR products were not obtained from the specimens of Patient 2. These results suggest that the relapse FCLs derived from a new clone. These FCL may develop as a secondary malignancy due to chemotherapy. Alternatively, the DLBL at presentation may contain a minor component of FCL, and chemotherapyresistant FCL may predominate after remission of chemotherapy-sensitive DLBL.
