CD34⁺ therapy-related acute promyelocytic leukemia in a patient previously treated for breast cancer

Therapy-related acute myeloid leukemia (AML) is a long term complication of chemotherapy for a variety of cancers. In most cases, the marrow demonstrates high risk cytogenetics and the prognosis is poor. In a minority of patients “good risk” cytogenetics, including t(15;17)(q22;q12), are seen and the patient’s prognosis is similar to those who have de novo disease. Currently we present a patient who developed therapy-related acute promyelocytic leukemia (APL) after chemoradiotherapy for breast cancer. This case was especially atypical because the leukemic cells were CD34⁺, which is an unusual immunophenotype for APL. Recognition that this patient had APL, rather than the more common therapy-related MDS or AML, was imperative to initiate chemotherapy in a timely manner.