Blastoid variant of mantle cell lymphoma:: late progression from classical mantle cell lymphoma and quantitation of minimal residual disease

Objectives: Classical mantle cell lymphoma (MCL) and its blastoid variant (MCL-BV) are characterized by an extremely poor prognosis. Long-time survivors are rare, only very few patients with an overall survival over 10 years have been reported. We present a case of a 41-year-old male with a 12 yr history of MCL stage I to show, that very late relapses in MCL are possible and may present as a transformation into an aggressive blastoid variant and to illustrate the value of quantitative minimal residual disease (MRD) monitoring for treatment guidance. Methods: Diagnostic lymph node and bone marrow samples were investigated by immunohistochemistry. Clonality analysis was performed by immunoglobulin heavy chain gene (IGVH) and t(11;14) PCR. The MRD assessment was done by real-time quantitative PCR (RQ-PCR) on available follow-up samples. Results: By histologic review and sequencing of the clonal IGVH and t(11;14) PCR products we demonstrated a common clonal origin of the leucemic MCL-BV and the classical MCL diagnosed 12 yr earlier. Quantitative MRD assessment revealed significant MRD levels after intensive conventional chemotherapy including Rituximab. Therefore, treatment was early intensified by myeloablative radio-chemotherapy and allogeneic peripheral stem cell transplantation from an unrelated HLA-identical donor. This did not translate into a sustained remission as reflected by persisting MRD levels after transplantation and the patient died from rapid progressive disease 3.5 months after transplant. Conclusion: This report presents a rare case of long-term survivor of MCL with a progression of the original MCL cell clone to MCL-BV and demonstrates the clinical value of quantitative MRD assessment for optimized therapeutic management.