Cardiac sarcoidosis: epidemiology, etiology, pathogenesis and pathomorphology (literature review)

Abstract

The review presents an analysis of current literature data on cardiac sarcoidosis (CS), the frequency of which varies widely in the structure of systemic sarcoidosis – from 3 to 39%. Many authors have noted a general upward trend in the prevalence and incidence of both systemic and CS, with variations depending on geographical region and ethnicity. It is suggested that the clinical phenotypes of CS differ depending on ethnic predisposition and sex. The role of human leukocyte antigen (HLA) polymorphism and specific alleles in the development of cardiac involvement in sarcoidosis has been investigated. The possible influence of infectious agents (Cutibacterium acnes, Mycobacterium tuberculosis, etc.) as an initiating factor in the development of the disease is considered. Non-caseating epithelioid granulomas, a specific morphological feature of sarcoidosis, can be localized in any part of the myocardium, leading to rhythm and conduction disturbances, the development of ventricular aneurysms, and heart failure. Multinucleated giant cells are detected in non-caseating epithelioid granulomas in no more than 20% of CS cases, and the absence of this specific pathomorphological feature does not rule out cardiac involvement in sarcoidosis. The staging of granulomatous inflammation supports the use of surrogate histopathological signs, including microgranulomas, clusters of M1-macrophages, signs of lymphangiogenesis, confluent fibrosis and fatty infiltration of the myocardium.