A Case of Therapy-Related Acute Myeloid Leukemia in a Patient With Heterozygous Mutations in the Ataxia Telangiectasia Mutated Gene

Use of adjuvant chemotherapy has improved survival for many patients with breast cancer. Unfortunately, such treatment can come at a price, in particular, malignancies. We present a case of a 36-year-old woman with heterozygous mutations in the ataxia telangiectasia mutated (ATM) gene who was admitted to the hospital for fatigue and diffusely scattered bruises. She was diagnosed with invasive ductal carcinoma of the left breast and had bilateral mastectomy with axillary node clearance followed by adjuvant chemotherapy 3 years prior. Her vitals were stable. Lab tests revealed thrombocytopenia, leukocytosis, and anemia. Peripheral blood smear and bone marrow biopsy revealed numerous myeloblasts. After flow cytometry and FISH analysis were performed, a diagnosis of therapy-related acute myeloid leukemia (t-AML) was made. The patient was treated with induction chemotherapy and a bone marrow biopsy revealed residual disease. Re-induction therapy was given and a bone marrow biopsy revealed complete remission. She subsequently received an allogenic stem cell transplant and was cured. Her treatment course was uncomplicated. We raise the question as to whether certain chemotherapy agents should be avoided in patients with mutations in DNA repair genes. Furthermore, it is essential for physicians to educate patients on the risk of secondary malignancies arising from chemotherapeutic treatment.