Differentiating HCLc from other B-cell disorders, such as splenic marginal zone lymphoma (SMZL), splenic B-cell lymphoma/leukaemia with prominent nucleoli (SLPN), encompassing HCLv and CD5 negative B-prolymphocytic leukemia (B-PLL), and splenic diffuse red pulp small B-cell lymphoma (SDRPL) is critical [30]. This evidence concerns the gene CD5 and splenic marginal zone lymphoma.