Co-expression of CD56 and CD30 in lymphomas with primary presentation in the skin: clinicopathologic, immunohistochemical and molecular analyses of seven cases

Background: Natural killer and natural killer-like T-cell lymphomas present ing in the skin usually demonstrate aggressive behavior, an angiocentric di stribution and a characteristic immunophenotype. In contrast, primary cutan eous CD30+ lymphoproliferative disorders form a heterogeneous spectrum incl uding anaplastic large cell lymphomas, the majority of which display a good prognosis. Lymphomas with coexpression of CD56 and CD30 are extremely rare and the significance of this co-expression is unknown. Methods: Seven retrospectively identified cases of lymphomas with co-expres sion of CD56 and CD30 presenting in the skin comprise this study. Immunohis tochemistry, in situ hybridization for Epstein-Barr virus and T-cell recept or gel-re rearrangement studies were performed on paraffin sections. Results: This subset of cutaneous lymphomas showed a variable clinical cour se that ranged from resolution without treatment, treatment-failure and rec urrence, to death from disease. Histologic, immunophenotypic and molecular studies were of limited utility in predicting prognosis. Conclusions: Cutaneous lymphomas co-expressing CD56 and CD30 share many cli nicopathologic features with natural killer and natural killer-like T-cell lymphomas or anaplastic large cell lymphomas, two entities with widely disp arate clinical behavior. It is important to recognize that these lymphomas may behave more aggressively than primary cutaneous anaplastic large cell l ymphomas do. Longer follow-up and further investigations on larger numbers of cases are necessary to fully characterize this rare subset of cutaneous lymphomas.