BACKGROUND Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease encountered in pediatrics with surgical repair being the definitive treatment. Long-term survival after surgical repair has improved; however, reported mortality rates in untreated TOF are significant. Associated complications include neurological sequelae such as brain abscess and stroke. In countries without early intervention for congenital heart disease (including TOF), delayed presentations and complications require recognition by healthcare workers. METHODS A 22-year-old male with a history of untreated TOF presented to Rwanda's tertiary university hospital, University Teaching Hospital of Kigali, with acute right-sided hemiparesis. Diagnostic imaging identified a left-sided brain lesion consistent with brain abscess and cardiac mass, concerning endocardial vegetation. He was managed with intravenous antibiotics but subsequently died due to complications of septicemia. CONCLUSIONS In countries where surgical repair of TOF is not available, early recognition and medical management are key in temporizing the development of devastating sequelae. Describing the prevalence of CHD in Rwanda is urgent, requiring further research by which effective prevention and treatment strategies can be developed.