CD5, or rarely, BCL6 or CD10 may be aberrantly expressed by the neoplastic cells [3,4], with the caveat that a background of CD10+ B cells corresponding to reactive germinal center cells may be detectable at flow cytometry, leading to misdiagnosis of MALT lymphoma as a reactive lesion; however, only about 50% of MALT lymphomas exhibit a distinct immunophenotypic aberrancy of the B cells. Here, CD5 is linked to MALT lymphoma.