Emerging spectrum of COVID-19-related cardiopulmonary pathology in adults

COVID-19 is currently a major cause of morbidity and mortality in adults throughout the world. Given the high infection rate, it is increasingly likely that histopathologists will encounter this disease during their practice. Although COVID-19 is increasingly recognized as a multi-system disease, the lungs and, to a lesser degree, the heart remain the major sites of pathology. This article aims to acquaint the general histopathologist with the main pathological findings in the lungs and heart of adults with COVID-19. It highlights the need for clinicopathological correlation with a discussion of the cardiopulmonary clinical features in COVID-19 and relates those to the pathological findings. In the lungs, diffuse alveolar damage is emphasized with its variety of morphological appearances over time. It concludes with a discussion of the main techniques available to identify the virus in fixed tissues and their potential limitations related specifically to the heart and lungs.