[Atypical onset of therapy-related acute promyelocytic leukemia after combined modality therapy including (89)Sr for metastatic breast cancer].

A 51-year-old woman diagnosed as having left breast cancer with axillary lymph node and liver metastases seven years earlier was seen in our office because of severe pancytopenia. She had received chemotherapy including several cycles of doxorubicin plus cyclophosphamide and docetaxel followed by hormone therapy containing leuprorelin and tamoxifen over four years. For management of bone pain due to metastasis, she had also undergone stereotaxic radiation therapy of the neck one and a half years earlier and unsealed internal radiation therapy with (89)Sr injection five months prior to the current presentation, Subsequently, myelosuppression progressively worsened and she finally required a blood transfusion. Although bone marrow examination showed severe hypoplasia, but neither blastic nor dysplastic, a test for PML-RARA fluorescence in situ hybridization was positive. After administration of all-trans retinoic acid, hematogenesis improved within three weeks. Neither disseminated intravascular coagulation nor retinoic acid syndrome was observed during the course of her illness. This is the first report describing acute promyelocytic leukemia after administration of (89)Sr, to our knowledge, and with an atypical onset and progression. As the number of cancer survivors increases due to improvements in medical intervention, clinicians must take more notice of special characteristics of therapy-related leukemia modified by previous treatments.