Eosinophilic myocarditis from a forensic histopathological perspective

Eosinophilic myocarditis (EM) is a rare and potentially fatal form of myocarditis characterized by infiltration of the myocardium with eosinophil leukocytes, often accompanied by eosinophilia. Although the exact underlying cause remains unknown, it has been shown to be associated with hypersensitivity reactions, immune-mediated disorders, infections, or cancer. Due to the differences in symptomatology, it is often diagnosed by postmortem histopathological examination. We aimed to retrospectively examine the histopathological findings of rare cases of EM and to detect accompanying cardiac and other organ pathologies. The histopathological findings of the cases that underwent autopsies between 2012 and 2020 and were diagnosed with EM were assessed. Demographic features, symptoms, causes of death, macroscopical findings at autopsy, toxicologic and microbiological analysis results, accompanying cardiac pathologies, and histopathological findings in other organs were evaluated. Myocarditis was detected on histopathologic examination in 558 (1.1%) of 49,612 forensic autopsies. There were 12 (2.3%) EM cases. There were nine males and four females. The mean age was 42.3 (3–83) years. Heart weights ranged from 82 to 564 g. The most common finding on macroscopic examination was the mottled discoloration and scarring in the myocardium. Microscopic examination revealed perivascular and interstitial infiltration of eosinophils in all of the cases accompanied by myocyte necrosis in four of them. EM was reported as the cause of death in four cases. EM remains a challenging heart disease with its obscure etiopathogenesis and varying clinical presentation and a rare entity diagnosed by postmortem histopathological examination in sudden and unexpected deaths.