Assessment of CD5-negative/CD10-negative B-cell NHL poses a diagnostic challenge, with the main diagnostic considerations being marginal zone lymphoma (MZL (Figure 4)) including splenic marginal zone lymphoma [SMZL], which represents a subset of MZL), splenic diffuse red pulp small B-cell lymphoma, CD10-negative follicular lymphoma, lymphoplasmacytic lymphoma (LPL), hairy cell leukemia (HCL) (Figure 5) and hairy cell leukemia variant (HCLv) (International Consensus Classification)/splenic B-cell lymphoma/leukemia with prominent nucleoli (WHO, 5th edition). This evidence concerns the gene MME and marginal zone lymphoma.