Clinicopathological study of fatal myocardial sarcoidosis

Presented here was an outline of fatal myocardial sarcoidosis in Japan based on 42 autopsy cases. The incidence, clinical features, pathological findings (particularly the distribution of sarcoid lesions in various organs, and gross as well as histological patterns have been reviewed. The ratio of fatal myocardial sarcoidosis to the total number of sarcoidosis deaths is higher than that of other countries and it appears characteristic of Japanese sarcoidosis that the disease occurs here predominantly after the fourth decade in females. Only 12% of myocardial sarcoidosis cases are diagnosed exactly. Conduction disturbances and dysrhythmias due to myocardial damage are its most common manifestations. The modes of presentation or cardiac death are sudden death, 16 cases (41%); congestive heart failure, 9 cases (23.1%); Adams-Stokes syndrome, except sudden death, 7 cases (17.9%); death due to dysrhythmia, 6 cases (15.4%); and 2 pacemaker deaths among the application of pacemakers, 7 cases. As for the ECG findings, A-V block and bundle-branch block was observed in most cases and ectopic beats were also frequently observed. The difficulty in exact diagnosis of myocardial sarcoidosis appears to be due to the frequency of lack of manifestation of systemic sarcoidosis as well as insidious cardiac involvement. The gross findings on myocardial lesions showed 3 patterns and each of the localized patterns corresponded to the histological extension. The conglomerate-band-like pattern corresponded to expansive invasion, the dendrite pattern to interstitial extension. The histological findings on the myocardial lesions were classified into four types: 1) exudative type, 2) granuloma type, 3) combined type of granuloma and fibrosis, 4) fibrotic type. Two extreme cases showed the exudative and fibrotic type, respectively, and were discussed.