Objective To explore the characteristics of clinical features,diagnosis,treatment and prognosis in acute fibrinous and organizing pneumonia (AFOP) patients.Methods We described an 80-year-old womanwho was diagnosed with AFOP and got better after treatment with glucocorticoids.Clinical data of 51 patients which have been published in literatures in China and abroad were retrospectively analyzed.The differences in characteristics of clinical features were compared between the elderly and non-elderlypatients.Results The case reported herein,who was a 80-year-old female with latent autoimmune diabetes in adults (LADA),presented with fever,dry cough and progressive dyspnea.Chest CT scan showed bilateral multiple patchy consolidation.CT-guided needle aspiration was performed and the pathological examination finding was consistent with AFOP.The patient was treated with oral methylprednisolone and experienced a significant improvement in symptoms and imaging manifestations.But she presented with deterioration with relapsing clinical symptoms when she discontinued corticosteroidtreatment by herself,and the clinical symptoms were improved by retreatment.Clinical data of 51 reported cases with AFOP including 27 males and 24 femalesaged 38 d to 80 years were enrolled and analyzed in the study.Patientsaged 60 years and over accounted for 47.1% (24 cases).No risk or predisposing factor was found in most of cases.Autoimmune diseases were the most common combined diseases in AFOP patients.The top three symptoms were dyspnea (80.4%,41 cases),cough (64.7%,33 cases) and fever (52.9%,27 cases).The incidence of dyspnea was lower in elderlypatients than in non-elderlypatients [66.7% (16/24) vs.92.6% (25/27),P<0.05],and ground glass opacity in the chest image was also less in elderlypatients than in non-elderlypatients (P<0.05).15 patients (29.4%) got definitive diagnosis by minimally invasive procedures including percutaneous lungpuncture biopsy or transbronchial lungbiopsy.Corticosteroids were the main drugtreatment,and 39 cases (76.5 %) received antibacterial drugs.The mortality rate of AFOP was 37.3% (15 cases).The average time from symptom onset to final diagnosis was shorter in dead cases than in recovered patients (19 days vs.40 days,P<0.05).The rate of using mechanical ventilation was higher in dead cases than in recovered patients [57.9 % (11/19) vs.9.4% (3/32),P<0.05].Conclusions There are no specific clinical and imaging features in AFOP,which is easily misdiagnosed as infectious diseases.AFOP is more common in elderlypatients.Dyspnea and other symptoms can easily be ignored,and minimally invasive biopsy and pathological examination findings is helpful for diagnosis.The mortality rate of AFOP is high,and insufficient course of therapy is associated with the increased risk of AFOP relapse.Rapid progression of disease and the invasive mechanical ventilation predispose poor outcomes.