Histopathological Insights Into Sino-Nasal Mucormycosis in COVID-19 Patients and Related Pathogenesis

Abstract Background: Rhino-orbital-cerebral mucormycosis (ROCM) is an aggressive fatal fungal infection in COVID-19 patients with uncontrolled diabetes and corticosteroids therapy. Aim of Study: Early and accurate diagnosis of mucormy-cosis focusing on the pathognomonic histopathological features and related pathogenesis. Patients and Methods: This retrospective study included 28 nasal biopsies of COVID-19 patients, between the first of January and the end of August 2021, data was collected from one tertiary center. Demographic, serological, radiological and clinical data were obtained from reports. Histopathological evaluation of H&E stained sections, PAS and Masson trichrome stains were done for each paraffin block. Results: A spectrum of histopathological features was noticed; the pathognomonic ones are: mycotic abscess with multiple giant cells and Emperipolesis, mycotic bone necrosis and/or osteonecrosis, paucicellular fat necrosis and angioin-vasion. Mucorales and associated Splendore-Hoeppli phenom-enon were obvious in all examined sections. About 35% of patients were children (4-13 years) with pre existing or concomitant diabetes, all were positive COVID-19 (PCR and/or radiological findings). Conclusions: Early histopathological diagnosis and new therapeutic modalities are safeguards against the co- morbidity of mucormycosis in COVID-19 patients. Authors declare no conflict of interest.