Histologically Confirmed Myxedematous Myocardial Involvement in Severe Hypothyroidism With Concomitant Bicuspid Aortic Stenosis
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Published on: October 20, 2023
Shubhang Sharma-Sharma1, Jaime Galindo-Uribe2, Sebastián Gutiérrez-Alanís2
1Department of Cardiology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico; Faculty of Medicine, National Autonomous University of Mexico, Mexico City, Mexico.
Background:
Histologically confirmed myxedematous myocardial involvement is rare and may be difficult to recognize when another cause of ventricular hypertrophy and fibrosis coexists.
Case Summary:
A 40-year-old man with longstanding, inadequately treated primary hypothyroidism presented with exertional dyspnea and a large goiter. Echocardiography showed severe bicuspid aortic stenosis, moderate aortic regurgitation, marked concentric left ventricular hypertrophy, preserved ejection fraction, and severely reduced global longitudinal strain. Cardiac magnetic resonance demonstrated extensive late gadolinium enhancement involving approximately 26% of myocardial mass. After thyroid optimization, he underwent aortic valve replacement. Myocardial biopsy showed severe cardiomyocyte atrophy, interstitial mucin deposition, and extensive replacement fibrosis; Congo red staining was negative.
Discussion:
Severe aortic stenosis provided an alternative explanation for the myocardial phenotype, and multimodality imaging alone could not distinguish pressure-overload remodeling from hypothyroidism-related myocardial injury.
Conclusion:
Histopathology established concomitant myxedematous myocardial involvement, highlighting the diagnostic value of tissue characterization in severe hypothyroidism.
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