IJCS | Volume 33, Nº4, July and August 2020

DOI: https://doi.org/10.36660/ijcs.20200033 Cardiac sarcoidosis (CS) is a rare and potentially fatal condition, characterizedby the presence of non-necrotizing granulomatous inflammation and concomitant fibrosis. A variety of clinical manifestation has been described, such as conduction disorders, ventricular arrythmias, congestive heart failure and sudden cardiac death, making a prompt diagnosis and early treatment desirable. Endomyocardial biopsy is the gold-standard diagnostic test, but has a lowsensitivity due to themultifocal aspect of the disease.Advanced imagingmodalities, such as cardiac magnetic resonance and positron emission tomography (PET) with 18F-fluorodeoxyglucose are now part of the diagnostic criteria and also assist in determining treatment response. However, the interpretation of those studies can be challenging and needs to be made by specialists, as the misdiagnosis could be harmful for the patient. This article describes the pathophysiology of CS and advanced imagingmodalities (with amajor focus on PET) that should be considered for diagnostic approach and therapy monitoring. Also, newer clinical trials evaluating treatment strategies are described. Introduction Systemic sarcoidosis (SS) was first describedmore than a century ago by the Norwegian dermatologist Caesar Boeck. He correlated skin nodules with epithelioid cells with large nuclei and giant cells as “multiple benign sarcoid of the skin”, for their resemblance with sarcoma. 1 Today, the cause of the disease remains unknown, but evidence points toward immunological response to an unidentified antigenic trigger in individuals with genetic susceptibility. 2 The estimation of the prevalence of SS in the population varies in the literature also depending on the type of study: epidemiologic, autopsy or imaging. Some previous data showed prevalence as high as 100- 330 cases per 100,000 inhabitants. 3,4 Environmental factors have been attributed to those differences, including sex, age and ethnicity, 5 showing a predisposition for environmental and genetic factors. The reported incidence is similar across sex in North American population but greater in females in Scandinavian and Japanese populations, 6,7 but more likely to be chronic and fatal in black Americans. 8 The disease usually develops before the age of 50 years, with a peak incidence at 20 to 39 years old, 9,10 and is very uncommon under the age or 15 or older than 70. 2 Symptomatic cardiac sarcoidosis (CS) has been reported in 2-5% of the patients with the systemic form. 11-13 However, with the advance of new cardiac imaging techniques, cases of asymptomatic (clinically silent) cardiac involvement have been diagnosed. 14 The disease has been reported in at least 20% of the autopsies and imaging report in the United States to as much as 50% in Japan. 7,15 Pathophysiology The presence of non-necrotizing granulomatous inflammation is the major characteristic of CS and is sometimes associated with fibrosis. Histologic proof of non-necrotizing granuloma differentiates CS from 389 REVIEW ARTICLE International Journal of Cardiovascular Sciences. 2020; 33(4):389-400 Mailing Address: ChristianeWiefels University of Ottawa Heart Institute 40, Ruskin Street, Ottawa, ON, K1Y 4W7, Canadá E-mail: cwiefels@ottawaheart.ca The Role of 18 F-FDG PET/CT in Cardiac Sarcoidosis Christiane Wiefels, 1, 2 O labimpe Lamai, 1 R iina Kandolin, 3 D avid Birnie ,1 Eugene Leung, 1 Claudio Tinoco Mesquita, 2 R ob Beanlands 3 University of Ottawa Heart Institute, 1 Ottawa – Canada Universidade Federal Fluminense, 2 Niterói, RJ – Brazil Heart and Lung Center, Helsinki University Central Hospital, 3 Helsinki – Finland Manuscript received February 27, 2020; revised manuscript April 27, 2020; accepted May 16, 2020. Cardiomyopathies; Sarcoidosis; Heart Failure; Metabolism Disorders; Sudden Cardiac Death; Diagnostic, Imaging; Magnetic Resonance Imaging/ diagnostic; Positron Emission Tomography Computed Tomography/diagnostic. Keywords