Peripheral B- and T-cell lymphomas may express immune phenotypes which differ from those seen on normal peripheral B- and T-cells, so-called aberrant phenotypes that may consist of atypical cross-lineage antigen expression, asynchronous-antigen expression, antigen overexpression, tissue-restricted phenotypes, abnormal maturation pathways. In our studies we reported two different types of aberrant phenotypes in malignant lymphoma.The aberrant expression of B-and T-cell markers may be not incidental but could be indicative of antigenic phenotype that has not been recognized previously. These cases with aberrant phenotypes require genotypic analysis for lineage assignment and studies of such cases may be helpful to better elucidate whether they represent a distinct entity with clinical, immunophenotypic and molecular characteristics or just an incidental phenomenon during malignant transformation.