Histological investigations of red focal changes. (A) Necrotic myocytes display pale cytoplasm and appear homogenous without striations (arrow). Myocyte with striations (asterisk) (HE staining). (B) Necrotic myocytes with erythrocytes apparently located within the myocytes (arrowheads) and some infiltrations of macrophage-like cells (arrow) (HE staining). (C) Centrally located vacuoles of varying size, surrounded by moderate levels of collagen (intense red) and modest numbers of leukocytes (van Gieson staining). (D) Focal haemorrhage surrounding vacuoles. The edges of the vacuoles are positive for ferric iron (blue colour) (Perls’ Berlin blue staining). (A, C) scale bar = 200 μm, (B) scale bar = 100 μm, (D) scale bar = 50 μm.