Fig. 2

Histopathological examination shows a large amount of coagulated necrotic tissue containing neutrophils, lymphocytes, eosinophils, multinucleated giant cells, and necrotic tissue (A1 H&E stain ×50; A2 H&E stain ×200). Folded, wrinkled, or swollen broad tubular hyphae are clearly observed under high magnification. Disordered hyphae rarely show branching; a few are visible as right-angled branches detached from the lateral wall, and the rest are seen as transversely cut round, oval, and polygonal unbranched cystic hyphae (B1 H&E stain ×200; B2 H&E stain ×400). Massive mycelial invasion is seen in the necrotic area of the spleen and in the blood vessels, with neutrophil infiltration both inside and outside the vessels, leading to fungal vasculitis (C1 H&E stain ×200; C2 H&E stain ×400). Periodic acid Schiff (PAS) stain shows the mycelium with pink walls (D1 PAS stain ×200; D2 PAS stain ×400). Grocott methylamine silver (GMS) stain shows the mycelium with brown–black walls (E1 GMS stain ×200; E2 GMS stain ×400)