Acute lymphoblastic leukemia presenting as myocardial infiltration mimicking hypertrophic cardiomyopathy: a case report.

Background: Acute lymphoblastic leukemia (ALL) with myocardial infiltration is a rare extramedullary manifestation, typically encountered in advanced or relapsed disease. Presentation as an isolated, reversible hypertrophic cardiomyopathy (HCM)-like phenotype without typical hematological symptoms is exceptional and poses a major diagnostic challenge. Case presentation: A 25-year-old man presented with fever, weight loss (20 kg over 3 months), progressive dyspnea, and bilateral lower extremity edema. Echocardiography and CMR imaging revealed severe asymmetrical left ventricular hypertrophy (maximum septal thickness 27 mm) with reduced left ventricular ejection fraction (as low as 27%), initially suggesting non-obstructive HCM. However, the presence of persistent fever, a marked inflammatory response (C-reactive protein 129 mg/L; reference: <10 mg/L), and elevated D-dimer and the lack of a family history or cardiovascular risk factors raised suspicion. Whole-body [ Conclusion: This case illustrates that T-ALL can first manifest as a rapidly progressive, HCM-mimicking cardiomyopathy that is fully reversible with effective chemotherapy. Clinicians should suspect hematologic malignancy in a young patient with unexplained cardiac hypertrophy associated with constitutional symptoms, elevated inflammatory markers, and poor response to standard therapy for heart failure. Early bone marrow examination and, if necessary, endomyocardial biopsy can confirm the diagnosis.