Not all that thickens is hypertrophic cardiomyopathy: a case report of unusual Takotsubo cardiomyopathy.

Background: Takotsubo cardiomyopathy (TTC) is an acute, reversible syndrome of left ventricular dysfunction typically triggered by stress and characterized by regional wall motion abnormalities often mimicking acute coronary syndrome. Although classically associated with apical ballooning, TTC can present with atypical patterns and may mimic structural cardiomyopathies, particularly apical hypertrophic cardiomyopathy (HCM). Transient myocardial oedema in TTC can result in reversible wall thickening and high signal intensity on cardiac magnetic resonance imaging, producing a pseudohypertrophic appearance that resembles HCM-a diagnostic pitfall with significant clinical implications. Case summary: We report a 74-year-old woman presenting with dyspnoea, elevated cardiac biomarkers, and echocardiographic apical ballooning. Coronary angiography revealed unobstructed coronary arteries, prompting consideration of TTC. Cardiac magnetic resonance performed 3 days later demonstrated global myocardial oedema, with disproportionate apical signal and cavity obliteration during systole mimicking HCM but no late gadolinium enhancement or infarction. The initial apical ballooning had resolved. The diagnosis of TTC with transient pseudohypertrophy due to myocardial oedema was made. The patient was commenced on guideline-directed heart failure therapy. Discussion: This case underscores the diagnostic complexity at the intersection of TTC, myocardial infarction with non-obstructive coronary arteries, and HCM mimics. Cardiac magnetic resonance was pivotal in revealing myocardial oedema and excluding infarction or fibrosis. Reversible wall thickening in TTC may resemble apical HCM, a phenomenon termed pseudohypertrophy. Takotsubo cardiomyopathy should remain a key differential despite angiographic findings. Early multimodal imaging is crucial for avoiding misdiagnosis and guiding appropriate management.