A 55-year-old male presents with generalized lymphadenopathy, splenomegaly, and peripheral lymphocytosis. A lymph node biopsy shows a diffuse effacement of the normal architecture by a monotonous population of small to medium-sized lymphocytes with irregular nuclear contours. Immunohistochemistry is positive for CD5, CD20, CD23 negative, and cyclin D1. Which of the following translocations is most likely to be found?

Explanation

The immunophenotype (CD5+, CD20+, CD23 negative, and cyclin D1 positive) combined with the morphology (monotonous population of small to medium-sized lymphocytes with irregular nuclear contours, diffuse growth pattern) is highly characteristic of Mantle Cell Lymphoma. Mantle Cell Lymphoma is defined by the t(11;14) translocation, which results in the overexpression of cyclin D1, a cell cycle regulatory protein. The clinical features of generalized lymphadenopathy and splenomegaly are also consistent with Mantle Cell Lymphoma. - t(8;14) is associated with Burkitt Lymphoma. - t(14;18) is associated with Follicular Lymphoma. - t(9;22) is the Philadelphia chromosome, associated with Chronic Myeloid Leukemia.