Mantle Cell Lymphoma with Marked Lymphocytosis at the Presentation and with Discordant Morphology Between the Lymph Node and Peripheral Blood

Abstract

A 72-year-old man was referred to our hospital because of lymphadenopathy, splenomegaly, and leukocytosis. His WBC count was 54,300/μl, with 89.6% atypical lymphocytes two to three times the diameter of red blood cells, cleaved nuclei, and one or two nucleoli. A lymph node specimen revealed a vaguely nodular pattern, and the diagnosis of mantle cell lymphoma (MCL) was made. The lymphoma cells appeared smaller and more mature than the leukemic cells. The phenotype of the peripheral blood and the lymph node cells was CD5⁺ CD10^- CD19⁺ CD20⁺ and the same rearranged J_H bands were detected, suggesting that their lymphocytes were of the same origin. In addition, the phenotype of the leukemic cells was CD23⁺ CD38⁺ CD43^- CD44⁺ FMC-7⁺ μ⁺ κ⁺. Cytogenetic analysis revealed complex anomalies but not t(11;14). Cyclin D1 protein was not detected. Because the lymphocyte morphology of the peripheral blood and lymph nodes was discordant, we speculated that variant large cells had proliferated mainly in the peripheral blood. The patient achieved a partial response after 6 courses of CHOP regimen, and was then placed on a COP regimen. He seemed to have MCL, but the following findings were unusual: marked lymphocytosis at initial presentation, discordant morphology, CD5⁺ CD10^- CD23⁺ CD43^- phenotype with neither t(11;14) or cyclin D1 over-expression.