MEITL shows a distinctive phenotype, and is positive for CD3, CD8 and CD56 in the majority of cases, however, pathologists need to be aware of phenotypic variation as CD8 and CD56 may be negative and the aberrant expression of CD20 may lead to a misdiagnosis of MEITL as a B-cell lymphoma. The gene discussed is NCAM1; the disease is B-cell non-Hodgkin lymphoma.