Unbalanced 11;18 translocation in an acute erythroid leukemia after radioactive iodine therapy

Therapy-related acute myeloid leukemia (t-AML) is well described after chemotherapy or radiotherapy for diverse malignancies. Radioisotope therapy is also recognized as a less-common cause of t-AML. We describe a patient with acute erythroid leukemia after radioactive iodine administration for papillary thyroid cancer, with an unbalanced 11;18 translocation resulting in three copies of 11q, including the MLL gene. Although an increased incidence of chronic myeloid leukemia has been documented after radioactive iodine exposure, acute leukemia in this setting has been less frequently seen. Moreover, to our knowledge, the chromosome abnormality present in our patient has not been previously reported. The literature on cytogenetic abnormalities in t-AML after radioactive iodine administration is reviewed.