Blastoid variant of mantle cell lymphoma with lactic acidosis: a case report.

Approximately 20% of mantle cell lymphomas (MCL) present with the blastoid variant associated with poor prognosis. Lactic acidosis complicated with hematologic malignancies is seen infrequently and is associated with a poor outcome. Here we report the case of a patient with the blastoid variant of MCL complicated by lactic acidosis and who achieved complete remission through chemotherapy combined with rituximab therapy. A 77-year-old man presented with peripheral blood lymphoma cells, huge splenomegaly, abdominal and mediastinal lymphadenopathy, and pleural effusion. A bone marrow smear showed an increase in large, abnormal lymphoid cells with oval or round nuclei, distinct nucleoli, and abundant basophilic cytoplasm with vacuolization. Splenic sections also showed massive and diffuse infiltration by these cells. Flow cytometry analysis showed these cells to be positive for CD5, CD19, CD20, and kappa chain and negative for CD10 and CD23. A blastoid variant of MCL was diagnosed from the results of histologic, immunohistochemical (cyclin D1), and cytogenetic (chimeric bcl-1/IgH fusion gene) analyses. The patient recovered from the 2 episodes of severe lactic acidosis for which he had been given chemotherapy, and he achieved complete remission after subsequent chemotherapy combined with rituximab treatment.