Multiple observational studies have described the similarities between COVID-19 pneumonia and organizing pneumonia (OP). These two entities clinically manifest with mild and subacute respiratory symptoms, often with a delayed diagnosis due to the atypical ARDS and silent hypoxemia presentation. Radiological features are often indistinguishable between the two. With the increase in antemortem lung biopsies and autopsies being performed, more histopathological findings of OP and its variant, acute fibrinous and organizing pneumonia (AFOP), are being diagnosed. These entities are known complications of viral infections as a delayed immunological process, explaining the favorable response to corticosteroids. Clinicians should be vigilant to diagnose this under-recognized entity of secondary OP in people with COVID-19 when clinical deterioration occurs, especially with compatible radiologic findings and recent cessation of corticosteroids. Despite the proven benefits of corticosteroids in treating COVID-19, treatment approaches can be more effective as OP often requires higher doses and a more prolonged therapy duration for remission and preventing relapses. The purpose of our narrative review is to compare the similarities between COVID-19 pneumonia and OP, emphasizing the clinical, radiological, and histopathological features based on the evidence available in the literature.

多项观察性研究描述了 COVID-19 肺炎和机化性肺炎 (OP) 之间的相似之处。这两种疾病在临床上表现为轻度和亚急性呼吸道症状，通常由于非典型 ARDS 和无症状低氧血症表现而导致诊断延迟。两者之间的放射学特征通常难以区分。随着死前肺活检和尸检的增加，越来越多的 OP 及其变异体急性纤维蛋白性机化性肺炎 (AFOP) 的组织病理学结果被诊断出来。这些实体是病毒感染的已知并发症，是一种延迟的免疫过程，解释了皮质类固醇的良好反应。当临床恶化时，临床医生应警惕地诊断 COVID-19 患者继发性 OP 的这一未被充分认识的实体，尤其是在放射学检查结果相一致且近期停止皮质类固醇的情况下。尽管皮质类固醇在治疗 COVID-19 方面已被证明具有益处，但治疗方法可能更有效，因为 OP 通常需要更高的剂量和更长的治疗持续时间才能缓解并防止复发。我们叙述性综述的目的是比较 COVID-19 肺炎和 OP 之间的相似性，强调基于文献中现有证据的临床、放射学和组织病理学特征。