Histopathologic Changes and Cellular Events of Organs Systems in COVID-19

A better understanding of histopathologic and cellular events of COVID-19 can help us to choose more proper management strategies and treatments. There are several ways to cellular and histopathologic evaluations; including, tissue sampling from living people as biopsies or dead people as autopsies or necropsies. In this study, we tried to evaluate the histopathologic concordance between findings of various tissue samplings derived from different sites that may work as a mirror of each other, especially mucocutaneous findings which may be indicative of similar events of other parts. Based on the main keywords, we searched databases of PubMed, Scopus, Google Scholar, Medscape, and CEBD coronavirus dermatology resource of Nottingham University and included the most relevant and well-designed studies with a higher level of pieces of evidence and higher sample size. In this study, selected pathological samples from different tissues of patients with COVID-19, including skin and mucosa, lungs, gastrointestinal tract, and kidneys were studied and summarized. Cellular changes and pathological findings in these patients were included by organ and listed by prevalence. Tissue sampling in patients with COVID-19 may help understand the pathophysiology of the disease as much as possible. Although most of these samples are taken after dying the patients, sampling before the more advanced stages of the disease could also show signs of tissue involvement before appearing the full systemic symptoms.