Indirect pathological indicators for cardiac sarcoidosis on endomyocardial biopsy

Abstract

Cardiac sarcoidosis is a myocardial inflammatory disease with non-caseating granulomas [1]. Cardiac sarcoidosis may be cardiac involvement of systemic sarcoidosis, although the heart may be the only organ involved. In contrast to pulmonary sarcoidosis, cardiac involvement of sarcoidosis is often associated with fatal outcome because of ventricular arrhythmia and ventricular dysfunction [2,3]. Clinical studies reveal cardiac involvement in 5%-10% of systemic sarcoidosis cases [4] but others suggest this involvement to be very rare (0.7%) [5] or very common (40%) based on symptomology [6]. The incidence in autopsy series was 20% in a 1952 study [7], but recent studies have demonstrated variable incidences of 27% [8], 76% in Caucasian patients [4], and 80% in Japanese patients [9]. This variability in incidence may be real; partly due to racial differences in prevalence and due to the development of diagnostic techniques such as the endobronchial ultrasound or cardiac positron emission tomography (PET) [10]. But it may also be related to the variable application of the current diagnostic criteria [1,11]. With respect to the pathologic diagnosis of cardiac involvement in systemic sarcoidosis, "the presence of non-caseating granuloma on histological examination of myocardial tissue with no alternative cause identified" is the current consensus by the Heart

Value of 3D mapping‐guided endomyocardial biopsy in cardiac sarcoidosis

“…The revised 2017 document from the Japanese Circulation Society (JCS) Joint Working Group establishes 4 specific criteria to diagnose ICS, including histopathological findings of monocyte infiltration and myocardial fibrosis as a minor criterion 27 . Other histopathological characteristics have been evaluated in previous research, to search for diagnostic surrogates for CS 28,29 . Literature on EAM‐guided EMB in CS is limited to case reports and only two case series (>1 patient) dated from 2014 (Table 3).…”

Histology of Cardiac Sarcoidosis with Novel Considerations Arranged upon a Pathologic Basis

“…Therefore, lesions where more than 30 to 50 cardiomyocytes culminate in necrosis are replaced with confluent fibrosis. Lipocytes occasionally infiltrate the myocardial complementary spaces where the volume of the myocardium is decreased owing to confluent fibrosis; this phenomenon is called fatty infiltration [ 36 ].…”

“…In histiocytic myocarditis, although typical sarcoidal granulomas are rarely distinctly recognized, several activated mononucleated macrophages collected in minute ill-defined nodules are occasionally termed “microgranulomas”. [ 36 ] There is no consensus on the size of the microgranuloma; however, it is representatively a minute nodular collection of 5 to 10 macrophages. Microgranulomas may be a diagnostic basis for cardiac sarcoidosis [ 36 ].…”

“…[ 36 ] There is no consensus on the size of the microgranuloma; however, it is representatively a minute nodular collection of 5 to 10 macrophages. Microgranulomas may be a diagnostic basis for cardiac sarcoidosis [ 36 ].…”

“…Microgranulomas and/or histiocytic accumulation are always associated with confluent fibrosis and fatty infiltration [ 36 ]. Confluent fibrosis is edematous fibrous tissue where more than 30 to 50 necrotized cardiomyocytes are replaced.…”