Pleuroparenchymal fibroelastosis in Korean patients: clinico-radiologic-pathologic features and 2-year follow-up

Abstract

Background/aims: Pleuroparenchymal fibroelastosis (PPFE) is a type of rare idiopathic interstitial pneumonia that is characterized by predominantly upper lobe involvement with pleural fibrosis and subjacent parenchymal fibrosis. This study aimed to determine the clinico-radiologic-pathologic features and prognosis of Korean patients with PPFE.

Methods: A total of 26 patients who were confirmed to have PPFE by lung biopsy, were included, and their clinico-radiologic-pathologic findings were retrospectively analyzed.

Results: The mean follow-up period was 23.8 months, and the mean age of the patients was 62.5 years; 61.5% were men and 50% were smokers. Cough and dyspnea were the most frequent presenting symptoms, and restrictive pattern was the most common observation in lung function. In 84.6% of the subjects, lower lobe involvement was found on chest computed tomography, and the usual interstitial pneumonia (UIP) pattern was the most common (59.1%). Among patients whose lower lobe was biopsied (n = 13), the UIP pattern was the most common (46.2%). Patients with lower lobe involvement were older and walked a shorter distance during the 6-minute walk test, compared to those without. Spontaneous pneumothorax was a common complication (26.9%), and 15.4% of the patients died mostly due to pneumonia (100%). The 1- and 3-year survival rates were 90.2% and 84.5%, respectively.

Conclusion: Clinical features of Korean patients with PPFE were similar to those reported previously; however, lower lobe involvement was more frequent. During follow-up, one-fourth of the patients experienced pneumothorax and one-fifth died from pneumonia.

Keywords: Idiopathic interstitial pneumonias; Pleural diseases; Pulmonary fibrosis; Survival analysis.

Figure 1.

Representative chest computed tomography images of patients with pleuroparenchymal fibroelastosis (PPFE). Images of the patients show the PPFE pattern in the upper lung and the usual interstitial pneumonia (UIP) pattern in the lower lung. (A) Coronal computed tomography (CT) images demonstrate the PPFE pattern in the upper lobe and the UIP pattern in the lower lobe. (B) Axial CT images show bilateral irregular-shaped subpleural nodular lesions, suggesting dense fibrosis in both upper lobes. (C) Axial CT image of the lower lung show areas of honeycombing cysts mixed with large emphysematous cysts, traction bronchiectasis, and coarse reticulation in both basal lungs, suggesting the UIP pattern.

Figure 2.

Changes in lung function and exercise capacity over time in patients with pleuroparenchymal fibroelastosis. Changes over 24 months in (A) forced vital capacity (FVC), (B) total lung capacity (TLC), (C) diffusing capacity of the lung for carbon monoxide (DLco), and in (D) distance, (E) initial saturation of peripheral oxygen (SpO₂), and (F), and the lowest SpO₂ during 6-minute walk test. Each plot represents the mean ± standard error of measurement of lung function or exercise capacity. ^a Significant decrease in outcome variables compared to the baseline value.

Figure 3.

Kaplan-Meier survival curves in patients with pleuroparenchymal fibroelastosis (PPFE). (A) Survival curves of total patients with PPFE. (B) Comparison of survival curves between PPFE patients with and without lower lobe involvement.