[CD56-positive acute myeloid leukemia patient with t(16;21)(p11.2;q22) relapsing with isolated pericardial effusion after HLA-haploidentical peripheral blood stem cell transplantation].

The rare chromosomal translocation t(16;21) has been associated with CD56 expression and extramedullary lesions in acute myeloid leukemia (AML). We herein report the first case of the development of isolated pericardial relapse after HLA-haploidentical peripheral blood stem cell transplantation (haplo-PBSCT). A 42-year-old male AML patient with t(16;21)(p11.2;q22) received haplo-PBSCT at partial remission, and he exhibited dyspnea due to massive pericardial effusion 11 months later. The effusion analysis revealed CD56+ leukemic cells, and G-banded karyotyping of the cells demonstrated t(16;21)(p11.2;q22). Salvage chemotherapy was administered, but only a transient improvement of the effusion was achieved. Moreover, the pleural effusion developed without bone marrow relapse.