We report the case of a 15-year-old female patient, native of the province of Chaco, diagnosed with lymphoblastic leukemia 2 years ago. She was currently in maintenance therapy, with good response to treatment. Twenty days before she began with headache and fever. At admission, blood cultures were negative, and brain computed tomography showed a hypodense lesion with involvement of white matter in left occipital-parietal area. A brain MRI was performed, and a hypointense left occipital lesion was observed in T1. The lesion showed peripheral gadolinium enhancing and was hyperintense on T2, with a hypodense central area surrounded by significant edema with mass effect. Chagas serology was positive, as well as the parasitemia. The patient was treated with benznidazole, with good response to therapy: a significant clinical improvement and mass reduction were observed, within the first month of treatment.