COVID-19: a Disease with a Potpourri of Histopathologic Findings—a Literature Review and Comparison to the Closely Related SARS and MERS

Abstract

Since the coronavirus disease 2019 (COVID-19) pandemic has hit the entire world, there is ample knowledge regarding its clinical course and prognostic biomarkers. Still, the pathophysiology of COVID-19 is poorly understood. Since the first guidelines published in February 2020 for autopsy of both confirmed and suspected COVID-19 cases, there has been an increasing number of autopsies and literature reporting histopathological findings. However, our knowledge about the immunological response of various organ systems to the virus, as well as response patterns, is inadequate but is essential to understand and initiate timely and targeted antiviral, anti-inflammatory, or anticoagulative therapy. Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is primarily considered a respiratory virus, current evidence shows that it causes life-threatening complications in almost all organ systems including the heart, brain, kidney, spleen, liver, and eyes. Hence, in this article, we reviewed the published case reports and case series in order to increase our understanding of COVID-19 pathophysiology. The main histopathological findings of the lungs include diffuse alveolar damage with activated type II pneumocytes, fibroblasts, protein-rich exudate, and hyaline membranes. Other significant histopathological findings include cardiomegaly, right ventricular dilation, splenic pulp atrophy, kidneys with severe podocytopathy, and collapsing glomerulopathy, and the brain showed hypoxic changes in the cerebellum and cerebrum. Furthermore, in this review, we also explained different pathological findings of SARS-CoV and MERS and compared them to SARS-CoV-2. This comprehensive review will improve our understanding of COVID-19 pathophysiology and various disease stages, hence promoting the application of targeted therapy.

Histopathologic findings on indication renal allograft biopsies after recovery from acute COVID‐19

“…reported a case of collapsing nephropathy with a borderline T‐cell‐mediated rejection in a KTR. Their patient had nephroangiosclerosis of native kidneys, and a transplant kidney biopsy performed in 2017 showed cellular rejection without evidence of collapsing glomerulopathy 9 . Another case of collapsing glomerulopathy in transplanted kidney was reported by Lazareth et al 10 .…”

“…A few cases of the glomerular disease have been reported, most commonly collapsing glomerulopathy. Other cases included minimal change disease, anti‐GBM disease, infection‐associated glomerulonephritis, membranous glomerulopathy, ANCA‐associated vasculitis and other less frequent findings, 8–29 summarized in Table 5. Various findings from different groups may indicate diverse problems present in specific populations.…”

“…Their patient had nephroangiosclerosis of native kidneys, and a transplant kidney biopsy performed in 2017 showed cellular rejection without evidence of collapsing glomerulopathy. 9 Another case of collapsing glomerulopathy in transplanted kidney was reported by Lazareth et al 10 sied patients, but do not specify the criteria for biopsy. 13 Our results…”

Atypical follicular hyperplasia with light chain–restricted germinal centers after COVID-19 booster: a diagnostic pitfall

“…Coronavirus disease 2019 (COVID-19) is a global pandemic, representing one of the most severe coronavirus diseases in humans in the past two decades [ 1 ]. COVID-19 disease is caused by the recently emerged severe acute respiratory syndrome (SARS)–related coronavirus species 2 or SARS-CoV-2 [ 2 , 3 ]. According to World Health Organization data, as of mid-May 2022, more than 525 million confirmed cases were documented worldwide, and more than 6.2 million deaths are attributed to COVID-19 [ 4 ].…”

2 Years into the Pandemic: What Did We Learn About the COVID-19 and Cerebellum?

“…The inflammatory changes typically target disrupted vascular walls suggesting prominent role of microvascular injury in COVID-19-induced neurological comorbidity [11]. The hypoxic changes are noticeable in COVID-19 patients with brainstem and cerebellar involvement [12].…”