Clonal B-Cell Lymphocytosis with Marginal Zone Features and Splenic Marginal Zone Lymphoma Share a Similar Cytogenetic and Mutational Profile

Introduction: Clonal B-cell lymphocytosis with marginal zone features (CBL-MZ) is a non-CLL type B-cell monoclonal lymphocytosis that has been recently recognized in the 2016 revision of the World Health Organization (WHO) classification of lymphoid neoplasms. Whether CBL-MZ corresponds to the early stage of splenic marginal zone lymphoma (SMZL) is not clearly defined. The aim of the study was to compare CBL-MZ and SMZL in patients diagnosed during the same period in two French university hospitals.