Expression of neural cell-adhesion molecule CD56 is a rare event in B-cell lymphoma. We described four cases of CD56-positive B-cell lymphoma, including follicular lymphoma and diffuse large B-cell lymphoma. These lymphoma cells expressed CD10 and bcl-6, which suggests germinal center-stage phenotype. Immunohistochemistry showed that CD56-positive cells aggregated and displayed a cohesive growth pattern, indicating that homotypic adhesion through the molecules might affect the manner of tumor growth and expansion. Although CD56 expression level varies among the cases, this molecule might play some roles in the manner of growth and expansion of CD56-positive B-cell lymphomas.