Massive idiopathic myocardial calcification presenting with a restrictive cardiomyopathy phenotype: diagnostic challenges in the differential diagnosis of constrictive pericarditis

Myocardial calcification is a rare pathological finding that, when extensive myocardial involvement is present, may lead to the development of restrictive cardiomyopathy and progressive heart failure. We report the case of a 57-year-old woman with long-standing heart failure and a restrictive cardiomyopathy phenotype of unknown etiology. Imaging studies demonstrated massive calcium deposits within the left ventricular myocardium and the interventricular septum. Computed tomography initially suggested constrictive pericarditis; however, subsequent echocardiographic assessment and cardiac magnetic resonance imaging supported the diagnosis of restrictive cardiomyopathy secondary to advanced myocardial fibrocalcinosis. No abnormalities of calcium-phosphate metabolism, chronic kidney disease, coronary artery disease, or any other convincing cause of dystrophic or metastatic calcification were identified. Following an extensive differential diagnostic evaluation, a diagnosis of idiopathic massive myocardial calcification was established. This case illustrates the considerable diagnostic challenges in differentiating restrictive cardiomyopathy from constrictive pericarditis and highlights the pivotal role of a multimodality imaging approach in achieving the correct diagnosis.