Microthrombosis as a cause of fulminant myocarditis-like presentation with COVID-19 proven by endomyocardial biopsy

Abstract

Myocardial injury has been reported as a complication of COVID-19. Although several mechanisms have been proposed as its cause, they are mostly based on autopsy studies, We report a 49-year-old male with COVID-19-associated myocardial injury presented like fulminant myocarditis. We performed endomyocardial biopsy on day 2 and we confirmed the presence of microthrombosis histologically. He died on day 5 due to cardiogenic shock.

Keywords: Biopsy; Cardiogenic shock; Cytokine storm; SARS-CoV-2.

Figure 1

Histology and immunohistology of endomyocardial biopsy samples. A. A focal small area of coagulative necrosis of myocytes (arrows) suggesting acute ischemic injury at microvascular level (Hematoxylin and eosin stain). The inset highlights the presence of a megakaryocyte within the capillary lumen. B. High-power view of a microthrombus with fibrin and platelets within the arteriole (arrow) in close proximity to the necrotic area in Figure 1A (Masson's trichrome stain). C. Scattered microthrombi (arrows) seen in microvessels (Masson's trichrome stain). D. High-power view of another microthrombus (arrow) accompanied by myocytes with diffuse cytoplasmic vacuolization. E and F. Immunostaining against CD61 showing platelets in obstructive and non-obstructive microthrombi in microvessels. G. Fibrin-rich microthrombus (arrow, Masson's trichrome stain) confirmed by phosphotungstic acid-hematoxylin (PTAH) stain (the inset). H.Arteriolar endothelial cell swelling is seen (Masson's trichrome stain). The inset highlights swollen endothelial cells in microvessels (immunostaining against CD31).