Figure 3.

Histology findings. Representative findings at histologic analysis of patients (P1–P7) are shown. (A) Hematoxylin-eosin assay in a patient (P7) with fulminant EBV myocarditis complicating COVID-19 infection; diffuse areas of necrosis and massive lymphocytic inflammatory infiltrates are shown; (B) mild lymphocytic infiltration without significant necrosis in a patient (P1) with borderline myocarditis; (C) trichrome assay in a patient (P6) with myocarditis (not shown) and likely preexisting dilated cardiomyopathy; multiple areas of replacement fibrosis (blue) are shown; (D) immunohistochemistry for CD3+ T-lymphocytes (>7/mm²) in fulminant myocarditis (P7); (E) in contrast, milder CD3+ infiltrated in a patient with mild inflammatory cardiomyopathy (P5); (F) CD68+ macrophage infiltrates in a patient with SARS-CoV-2 borderline myocarditis (P2). Scale bars: (A): 100 µm; (B,E,F): 50 µm; (C,D): 200 µm. CD = cluster of differentiation; EBV = Epstein–Barr virus; SARS-CoV2 = severe acute respiratory syndrome coronavirus-2.