Evaluation of Cadaver Lung Tissue and the Histologic Characterization of Viral Interstitial Pneumonitis Background Histologic characterization offers a framework for the understanding and diagnosis of viral interstitial pneumonitis (VIP). Moreover, due to the serious consequence in delayed diagnosis, in particular respiratory failure, the clinical findings and physiology of interstitial pneumonitis are fundamental to prevent mortality. Previous studies highlighted the high mortality associated with respiratory failure from VIP, emphasizing the urgency of diagnosis and treatment 1. Thus, there is a need for earlier detection and treatment of VIP. Here, human cadaver lung tissue is evaluated and characterized in a cadaver with a known cause of death of “respiratory failure.” Notably, cadaveric studies are relevant due to pathological study of human remains being the gold standard for the diagnosis of many diseases. Methods Human lung tissue specimens were collected by dissection from a donated cadaver made available by the department of anatomy. The samples were processed as standard tissue specimens to create hematoxylin-eosin stained slides. A board-certified pathologist evaluated the slides under a light microscope to assess alveolar morphology, immune cells, and tissue architecture. Results The histologic slides were high quality without evidence of staining or other artifacts from the embalming process. The lung sections showed diffuse thickening of the alveolar septa with some cuboidalization of the alveolar epithelium. Furthermore, there was presence of a predominantly lymphocytic infiltrate within the lung interstitium, in the absence of bacteria. Together, these findings are highly suggestive of viral interstitial pneumonitis as the underlying mechanism of death. Conclusion Lung tissue from human cadavers is particularly useful to observe the histologic manifestations of lung disease. This cadaveric study and microscopic findings highlight the feasibility in histologic analysis to diagnose viral interstitial pneumonitis. In contrast to the neutrophil-predominant intra-alveolar exudate seen in pneumonia, VIP presents with lymphocyte-predominant interstitial inflammatory infiltrate. By leveraging lung samples and histological analysis at an earlier time, physicians can more rapidly diagnose VIP and initiate appropriate therapy. This ultimately will reduce the risk of respiratory failure and prevent mortality.