Blastoid mantle cell lymphoma occurring in a patient in complete remission of chronic myelogenous leukemia.

The development of a de novo lymphoma in patients affected by chronic myelogenous leukemia (CML) is a rare event. The introduction of new molecular cytogenetic techniques, such as fluorescence in situ hybridization (FISH), allows a correct differential diagnosis between lymphoid blastic crisis and a blastoid variant of mantle cell lymphoma (MCL), which shows an aggressive behavior and some molecular characteristics detectable by cytogenetics and immunohistochemistry. We report a case of a blastoid variant of MCL that developed in a patient with CML who achieved complete cytogenetic and molecular response to imatinib mesylate treatment.