Objective: To summarize the clinical features of 21 cases of acute fibrinous and organizing pneumonia (AFOP) confirmed by pathology, thereby improving clinicians' understanding of this disease and avoiding misdiagnosis in clinical practice. Methods: Twenty-one patients diagnosed pathologically with AFOP from January 2016 to April 2019 were analyzed retrospectively. The clinical symptoms, laboratory examination results, imaging features, treatments and outcomes were analyzed comprehensively. Results: There were 10 males and 11 females, with an average age of (58±10) years. All the cases presented subacute disease onset. The main symptoms were cough, expectoration and fever. The results from laboratory examination showed that the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were significantly higher than the normal levels. The total number of leukocytes, the percentage of neutrophils, and procalcitonin were also higher than the normal levels. Among these patients, 4 cases showed positive sputum bacteriology. Nine patients were found to have probable etiological factors (infections in 4, tumors in 4 cases, and connective tissue disease in 1 case). Twelve patients had no confirmed etiological factors. As to radiological findings, the patterns were multiple patchy infiltrates(16/21), solitary mass (3/21) and multiple nodules in both lungs (2/21). Most lesions were subpleural in distribution (15/21), with air bronchogram sign (11/21), pleural effusion (9/21), and cavity (4/21). Three patients received anti-infective therapy only. The infiltration in lung disappeared within 2 months in one patient, but the lesion still existed in one case after three years of follow-up. However, one patient were lost during the follow-up. Eighteen patients were treated with oral glucocorticoids, and about 50% of the patients showed significant improvement in symptoms and imaging findings within one month. The average follow-up time was (22±10) months, and there was no death. Conclusions: The clinical and imaging findings of AFOP are nonspecific. The exact mechanism of its pathogenesis is not clear. Infection and tumor may be related to the pathogenesis of AFOP. AFOP with subacute onset has a good response to glucocorticoid treatment with a better prognosis.
目的： 分析经病理确诊的21例急性纤维素性机化性肺炎（AFOP）患者的临床特点。 方法： 回顾性纳入2016年1月至2019年4月经病理确诊的21例AFOP患者，其中男10例，女11例，年龄41~79岁，平均（58±10）岁。对患者的临床症状、实验室检查结果、影像学特征、治疗及转归进行综合分析。 结果： 本组病例均为亚急性起病，患者症状主要为咳嗽、咳痰、发热。9例患者可能有发病相关原因（4例感染相关、4例肿瘤相关、1例结缔组织病），12例患者暂无明确的发病相关因素。实验室检查结果显示，AFOP患者C反应蛋白及ESR明显高于正常水平，外周血白细胞总数、中性粒细胞百分比及降钙素原也高于正常水平；痰液病原学检查阳性者4例。影像学表现为斑片状实变影（16/21）、孤立性肿块（3/21）和两肺多发结节（2/21）；病灶多呈胸膜下分布（15/21），合并支气管充气征（11/21）、胸腔积液（9/21）和空洞（4/21）。3例患者仅接受抗感染治疗，1例患者2个月内病灶吸收，1例随访3年病灶仍存在，1例失访；18例患者口服糖皮质激素治疗，约半数1个月内症状和影像学表现明显改善。 结论： AFOP临床和影像学表现无特异性，发病的确切机制尚不明确，感染和肿瘤可能与AFOP发病相关，亚急性起病的AFOP患者对糖皮质激素治疗反应好，预后较好。.
Keywords: Acute fibrinous and organizing pneumonia; Fibrin balls; Interstitial pneumonia; Organizing pneumonia.