Evidence of immunopathological traces in mucormycosis: an autopsy case

A 77-year-old diabetic man newly contracted pulmonary mucormycosis. A rapidly progressing clinical course including severe worsening of pneumonia and renal failure culminated in death. This patient presented with hypocomplementemia and dermal vasculitis. Autopsied organs were examined by histological technique. Lung tissues showed pulmonary artery thrombosis and extensive alveolar invasion by Mucor hyphae with depositions of immunoglobulins, mannose-binding lectin (MBL) and C1q. The right internal jugular vein was occluded by thrombi containing numerous hyphae. The glomerular change was a hallmark of extra-capillary proliferative glomerulonephritis, which was overlying diabetic nephropathy. Depositions of IgM, C3 and C4 on glomeruli were also detected. Electron microscopy showed electron-dense deposits in the mesangial area and the wall of the afferent arteriole. This report shows evidence of complement opsonization of Mucor hyphae and refers to mucormycosis that developed small-sized vasculitis with complement activation.