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Blastoid and pleomorphic mantle cell lymphoma: still a diagnostic and therapeutic challenge!

Martin Dreyling, Wolfram Klapper and Simon Rule

Abstract

Blastoid mantle cell lymphoma is characterized by highly aggressive features and a dismal clinical course. These blastoid and pleomorphic variants are defined by cytomorphological features, but the criteria are somewhat subjective. The diagnosis may be supported by a high cell proliferation based on the Ki-67 labelling index. Recent analysis have shown that the Ki-67 index overrules the prognostic derived from the cytology subtypes. Nevertheless, genetic analysis suggests that blastoid and pleomorphic variants are distinct from classical mantle cell lymphoma. In clinical cohorts the frequency of this subset varies widely but probably represents about 10% of all cases. Chemotherapy regimens commonly used in mantle cell lymphoma such as bendamustine rarely achieve prolonged remissions once applied in the dosage developed for classical variants of the disease. Thus, high dose cytarabine containing regimens with high dose consolidation may be generally recommended based on the more aggressive clinical course of these patients. However, even with these intensified regimens the long term outcome seems to be impaired. Thus, especially in this patient subset allogeneic transplantation may be discussed at an early timepoint of the disease management. Accordingly, targeted approaches are warranted in these patients but clinical data are scarce. Ibrutinib treatment achieves high rates of responses but median duration of remission is less than 6 months. Similarly, lenalidomide and temsirolimus achieve only short term remissions. Novel approaches like CAR T-cells may have the potential to finally improve the so far dismal long term outcome of these patients.

  • Submitted August 10, 2017.
  • Accepted October 26, 2018.