Distinct characteristics of pleuroparenchymal fibroelastosis with usual interstitial pneumonia compared with idiopathic pulmonary fibrosis

Incidental Apical Pleuroparenchymal Scarring on Computed Tomography: Diagnostic Yield, Progression, Morphologic Features and Clinical Significance

PURPOSE

Apical pleuroparenchymal scarring (APPS) is commonly seen on chest computed tomography (CT), though the imaging and clinical features, to the best of our knowledge, have never been studied. The purpose was to understand APPS's typical morphologic appearance and associated clinical features.

PATIENTS AND METHODS

A random generator selected 1000 adult patients from all 21516 chest CTs performed at urban outpatient centers from January 1, 2016 to December 31, 2016. Patients with obscuring apical diseases were excluded to eliminate confounding factors. After exclusions, 780 patients (median age: 64 y; interquartile range: 56 to 72 y; 55% males) were included for analysis. Two radiologists evaluated the lung apices of each CT for the extent of abnormality in the axial plane (mild: <5 mm, moderate: 5 to 10 mm, severe: >10 mm), craniocaudal plane (extension halfway to the aortic arch, more than halfway, vs below the arch), the predominant pattern (nodular vs reticular and symmetry), and progression. Cohen kappa coefficient was used to assess radiologists' agreement in scoring. Ordinal logistic regression was used to determine associations of clinical and imaging variables with APPS.

RESULTS

APPS was present on 65% (507/780) of chest CTs (54% mild axial; 80% mild craniocaudal). The predominant pattern was nodular and symmetric. Greater age, female sex, lower body mass index, greater height, and white race were associated with more extensive APPS. APPS was not found to be associated with lung cancer in this cohort.

CONCLUSION

Classifying APPS by the extent of disease in the axial or craniocaudal planes, in addition to the predominant pattern, enabled statistically significant associations to be determined, which may aid in understanding the pathophysiology of apical scarring and potential associated risks.

A Rare Case of Idiopathic Pleuro-Parenchymal Fibroelastosis Presenting With Bilateral Spontaneous Pneumothoraces

Pleuroparenchymal fibroelastosis (PPFE) is a rare interstitial lung disease (ILD), characterized by predominantly upper lobe pleural and subjacent sub-pleural parenchymal fibrosis. Its name refers to a combination of fibrosis involving the visceral pleura with fibroelastotic changes, predominantly in the subpleural lung parenchyma. We describe the case of a 67-year-old lady who presented to the accident and emergency department of Weston General Hospital with worsening shortness of breath (SOB) and cachexia of six to eight months' duration. The initial imaging studies showed bilateral spontaneous pneumothoraces on a background of pleural-based consolidation and fibrotic changes. A subsequent high-resolution CT (HRCT) chest showed evidence of pleuroparenchymal fibroelastosis in the background. She was not considered for anti-fibrotic medications due to the advanced stage of the disease and was managed with supportive measures, including oxygen support, oral steroids and antibiotics to cover for any infections. After initial management of symptoms and long discussions with the patient, family and the palliative team, she was discharged home with community follow-up.

Development of microscopic polyangiitis following idiopathic pleuroparenchymal l fibroelastosis: A case report

Idiopathic pleuroparenchymal fibroelastosis (PPFE) is a rare type of idiopathic interstitial pneumonia, which is characterised by pleural fibrosis and subjacent parenchymal fibroelastosis of the upper lobes. Herein, we present a case of microscopic polyangiitis (MPA) following PPFE. The patient had abnormal shadows on chest radiographs 15 years before the onset of MPA, and the patient was diagnosed with PPFE. Four years after the PPFE diagnosis, the patient was diagnosed with MPA based on persistent fever, purpura, mononeuritis multiplex, myeloperoxidase-antineutrophil cytoplasmic antibody positivity, and pathological findings of peritubular capillaritis on kidney biopsy. The patient was treated with glucocorticoids, including methylprednisolone pulse therapy and rituximab, followed by maintenance therapy with rituximab. One year after treatment, the PPFE had not worsened. PPFE occasionally occurs secondary to connective tissue disease, including MPA; however, to the best of our knowledge, this is the first report of PPFE preceding MPA. Our case suggests that PPFE, as other interstitial lung diseases, may be associated with MPA and precede the onset of MPA. The accumulation of more cases is needed to clarify the characteristics of MPA-associated PPFE.

Pulmonary fibroelastosis - A review

Elastin is a long-lived fibrous protein that is abundant in the extracellular matrix of the lung. Elastic fibers provide the lung the characteristic elasticity during inhalation with recoil during exhalation thereby ensuring efficient gas exchange. Excessive deposition of elastin and other extracellular matrix proteins reduces lung compliance by impairing ventilation and compromising gas exchange. Notably, the degree of elastosis is associated with the progressive decline in lung function and survival in patients with interstitial lung diseases. Currently there are no proven therapies which effectively reduce the elastin burden in the lung nor prevent dysregulated elastosis. This review describes elastin's role in the healthy lung, summarizes elastosis in pulmonary diseases, and evaluates the current understanding of elastin regulation and dysregulation with the goal of guiding future research efforts to develop novel and effective therapies.

Pleuroparenchymal Fibroelastosis-like Lesions in Clinical Practice: A Rare Entity? Review of a Radiological Database

Background: Pleuroparenchymal Fibroelastosis (PPFE) is a rare disease that consists of elastofibrosis that involves the pleura and subpleural lung parenchyma; it is an unusual pulmonary disease with unique clinical, radiological and pathological characteristics. According to recent studies, PPFE may not be a definite disease but a form of chronic lung injury. The aim of this retrospective study is to determine the incidence and to evaluate the distribution, severity and progression of this radiological entity on high-resolution CT (HRCT) exams of the chest, performed in routine clinical practice. In total, 1514 HRCT exams performed in the period January 2016-June 2018 were analyzed. For each exam, the presence of PPFE was evaluated and a quantitative score was assigned (from 0 to 7 points, based on the maximum depth of fibrotic involvement of the parenchyma). When available, two exams with a time interval of at least 6 months were compared for each patient in order to evaluate progression (defined as the increase in the disease score). Patients were divided into different groups according to exposure and their associated diseases. Statistical analysis was performed by using the Wilcoxon test and Kruskal-Wallis test. Results: PPFE was detected in 174 out of 1514 patients (11.6%), with a mean score of 6.1 ± 3.9 (range 1-14). In 106 out of 174 patients (60.9%), a previous CT scan was available and an evolution of PPFE was detected in 19 of these (11.5%). Among these 19 patients with worsening PPFE, 4 had isolated PPFE that was associated with chronic exposure or connective tissue disorders, and the other 15 had an associated lung disease and/or a chronic exposure. In this group, it was found that the ventral segments of the upper lobes, fissures and apical segments of the lower lobes had a greater statistically significant involvement in the progression of the disease compared to the non-progressive group. In 16 of 174 patients (9.2%, 7 of which belonged to the radiological progression group) a biopsy through video-assisted thoracoscopic surgery or apicoectomy confirmed PPFE. Conclusion: PPFE-like lesions are not uncommon on HRCT exams in routine clinical practice, and are frequently found in patients with different forms of chronic lung injury. Further studies are necessary to explain why the disease progresses in some cases, while in most, it remains stationary over time.

The world of rare interstitial lung diseases

The world of rare interstitial lung diseases (ILDs) is diverse and complex. Diagnosis and therapy usually pose challenges. This review describes a selection of rare and ultrarare ILDs including pulmonary alveolar proteinosis, pulmonary alveolar microlithiasis and pleuroparenchymal fibroelastosis. In addition, monogenic ILDs or ILDs in congenital syndromes and various multiple cystic lung diseases will be discussed. All these conditions are part of the scope of the European Reference Network on rare respiratory diseases (ERN-LUNG). Epidemiology, pathogenesis, diagnostics and treatment of each disease are presented.

Clinical features of idiopathic pleuroparenchymal fibroelastosis with progressive phenotype showing a decline in forced vital capacity

BACKGROUND

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is heterogeneous, with some patients showing a progressive decline in forced vital capacity (FVC). However, the clinical features of these cases with progressive phenotypes remain unknown.

METHODS

This retrospective study included 48 patients diagnosed with IPPFE who underwent longitudinal pulmonary function tests at our institution from 2005 to 2021. The progressive phenotype was defined as a relative decline of ≥10% in %FVC within two years from diagnosis of IPPFE, and its clinical features were evaluated.

RESULTS

Of the 48 patients, 23 (47.9%) were classified as progressive IPPFE. They were significantly older with a higher rate of dyspnea, fine crackles on chest auscultation, lower-lobe usual interstitial pneumonia (UIP) pattern on high-resolution computed tomography, and lower %FVC at diagnosis than non-progressive IPPFE. Additionally, progressive IPPFE had a significantly higher rate of long-term oxygen therapy requirement, the incidence of pneumothorax, and weight loss after diagnosis, which showed worse survival than non-progressive IPPFE. The relative decline in %FVC and weight loss showed a significant positive correlation. Multivariate analysis revealed that lower body mass index tended to predict early progression, and the coexistence of lower-lobe UIP pattern was significantly associated with early progression. A decline in %FVC was an independent poor prognostic factor in IPPFE.

CONCLUSIONS

With a progressive decline in %FVC, IPPFE often has an advanced stage at diagnosis and lower-lobe UIP pattern and is associated with weight loss and worse survival.

Acute exacerbation of pleuroparenchymal fibroelastosis with lower lobe usual interstitial pneumonia: An autopsy case

An 87-year-old man presented with dyspnea. Computed tomography revealed progressive subpleural consolidation in the apex, reticular shadows in the lower lobes, and bilateral ground glass opacifications. He died of respiratory failure on day 3. The post-mortem examination showed exudative stage diffuse alveolar damage and pulmonary edema. Intraalveolar collagenous fibrosis and subpleural elastosis were observed in the upper lobes, accompanied by interlobular septal and pleural thickening and lung architecture remodeling in the lower lobes. He was diagnosed with acute exacerbation of pleuroparenchymal fibroelastosis with lower lobe usual interstitial pneumonia, which can be fatal.

Idiopathic pleuroparenchymal fibroelastosis

The term idiopathic pleuroparenchymal fibroelastosis refers to a rare interstitial lung disease that predominantly involves the upper lobes. It has been considered a rare subtype of interstitial lung disease since 2013, when it was included in the joint consensus statement on the diagnosis of interstitial lung diseases published by the American Thoracic Society (ATS) and the European Respiratory Society (ERS). Currently, two distinct types of pleuroparenchymal fibroelastosis are recognized: the idiopathic type for cases in which it has not been possible to establish a specific etiology and a secondary type associated with a variety of different causes. The diagnosis of pleuroparenchymal fibroelastosis must be managed from a combined clinical and radiological perspective. High-resolution computed tomography (HRCT) is the imaging method of choice for the evaluation and diagnosis of pleuroparenchymal fibroelastosis. In many cases, the diagnosis will be based exclusively on the HRCT findings and histologic confirmation will be unnecessary. This article describes the clinical, radiological, and histological characteristics of pleuroparenchymal fibroelastosis, discussing the different associations with this entity and its differential diagnosis.

Prognostic significance of radiological pleuroparenchymal fibroelastosis inMycobacterium aviumcomplex lung disease: a multicentre retrospective cohort study

Background

Mycobacterium aviumcomplex (MAC) causes chronic respiratory infectious diseases with diverse clinical features and prognoses. Pleuroparenchymal fibroelastosis (PPFE) is a rare disease characterised by pleural fibrosis with subjacent intra-alveolar fibrosis and alveolar septal elastosis, with unique chest high-resolution CT (HRCT) features (radiological PPFE). An association between recurrent respiratory infections and PPFE formation has been hypothesised; however, the clinical significance of PPFE in MAC lung disease remains unclear.

Methods

This retrospective, multicentre study investigated the prevalence of radiological PPFE in patients with MAC lung disease and its association with clinical features and outcomes. Radiological PPFE was diagnosed on the basis of HRCT findings. Prognostic factors were identified using Cox proportional hazards and Fine-Gray models.

Results

Of 850 consecutive patients with definite MAC lung disease, 101 (11.9%) exhibited radiological PPFE. Patients with radiological PPFE had unique characteristics, such as lower body mass index, lower survival rate (5-year cumulative survival rate, 63.1% vs 91.7%; p<0.001) and a higher incidence of respiratory-related death (5-year cumulative incidence, 31.1% vs 3.6%; p<0.001), than those without radiological PPFE. In the multivariable analysis, the presence of radiological PPFE was independently associated with all-cause mortality (adjusted HR, 4.78; 95% CI, 2.87 to 7.95; p<0.001) and respiratory-related death (adjusted HR, 3.88; 95% CI, 2.14 to 7.01; p<0.001).

Interpretation

This large-scale study demonstrated that in patients with MAC lung disease, radiological PPFE was common, a phenotype associated with unique clinical features and poor prognosis, particularly respiratory-related death. The specific management of this subgroup should be established.

Diagnosis of pleuroparenchymal fibroelastosis: A review

Pleuroparenchymal fibroelastosis (PPFE) is a rare lung disease with unprecedented features characterized by fibroelastotic changes in the subpleural lung parenchyma affecting the upper lobes. PPFE is usually idiopathic, but it can be caused by infection, autoimmunity, bone marrow or lung transplantation, or a genetic predisposition. Histopathologic examination of lung biopsy samples reveals homogenous subpleural fibrosis and abundant elastic fibers, allowing for a definitive diagnosis. As PPFE mimics many interstitial lung diseases, clinicians face significant difficulties in making a definitive final diagnosis. Since most disease-related comorbid conditions manifest at an advanced stage, invasive tissue sampling for histopathologic evaluation is consistently impossible. Such a patient presentation highlights the importance of an analysis based solely on clinical findings, which would provide a definitive diagnosis without the need for a biopsy. Because of its exceptional and inconceivable presentation, PPFE creates a diagnostic dilemma. In light of our two cases and the literature data, we present a diagnostic assessment score assay that relies solely on clinical manifestations without histopathological tissue verification to shed light on the diagnosis of PPFE. This review focuses on PPFE identification through the use of a diagnostic assessment analysis to improve early disease recognition without the use of invasive diagnostic interventions to obtain biopsy samples for histopathologic evaluation. This analytic approach, while not diagnostic in and of itself, may provide a useful pathway for differential diagnosis and may preclude redundant initiatives.

Determinants of Six-Minute Walk Distance in Idiopathic Pulmonary Fibrosis and Idiopathic Pleuroparenchymal Fibroelastosis

Background: In idiopathic pulmonary fibrosis (IPF), 6-minute walking distance (6MWD) is an independent factor for mortality. Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is a rare disease with physical features such as emaciation, but the relationship between IPPFE and 6MWD is unclear. In this study, we investigated the factors that cause a decrease in the percent of the predicted value of a 6-minute walk distance (%6MWD), including the disease entities, IPF and IPPFE. Methods: This study included 100 patients (IPF: 75 patients, IPPFE: 25 patients, age: 73.5 ± 7.2 years, sex: 73 males) who visited the rehabilitation department. Patients with a %6MWD ≥ 80% were assigned to the normal group (n = 54), and patients with a %6MWD < 80% were assigned to the decreased group (n = 46). The items showing a significant difference between groups were used as independent variables, after the consideration of multicollinearity, for a logistic analysis where %6MWD < 80% was used as the dependent variable. Results: The 6MWD results show that there was no significant difference between IPF and IPPFE in the absolute value of 6MWD and in the number of people with 6MWD ≥ 250 m, but when 6MWD was compared with %6MWD, the IPPFE group showed a significantly lower value than the IPF group (p = 0.013). Logistic regression analysis showed that only BMI (p = 0.032), GAP index (p = 0.043), and mMRC (p = 0.026) were factors that caused a decrease in %6MWD in 100 patients. Conclusion: The results suggest that leanness, shortness of breath and severity of illness are the most important factors that determine exercise tolerance, regardless of disease entity in IPF and IPPFE.

Pleuroparenchymal Fibroelastosis: A Case Report

Pleuroparenchymal fibroelastosis (PPFE) is a rare, idiopathic interstitial pneumonia. wherein the first symptom might be dyspnea or a dry cough. The condition can also be manifested with chest pain secondary to pneumothorax. While the definitive diagnosis is based on a histological evaluation (which is not often performed), a computed tomography scan shows findings, such as apical fibrosis and pleural thickening of the apical lobes, which help assess the diagnosis. We describe a case of PPFE diagnosed radiologically in a 69-year-old man. This case highlights that PPFE is a pathology that can go unnoticed for a long time, and patients might neglect the revealing symptoms such as coughing.

Pleuroparenchymal fibroelastosis

PURPOSE OF REVIEW

Pleuroparenchymal fibroelastosis (PPFE) is a clinico-radiologic-pathologic interstitial lung disease (ILD) characterized by fibrosis that has upper lobe and subpleural predominance, involving both the visceral pleura and the subjacent subpleural lung parenchyma, and comprises dense fibroelastic changes with prominent elastosis of the alveolar walls together with fibrous thickening of the visceral pleura. The goal of this review is to summarize the state-of-the-art understanding in PPFE.

RECENT FINDINGS

PPFE was described in an increasing number of conditions. The course of disease is heterogeneous. Idiopathic PPFE, cases associated with telomerase-related gene mutations, cases related to a history of chemotherapy, and cases combining PPFE with a pattern of usual interstitial pneumonia, may have a particularly poor prognosis. Well-conducted retrospective studies identified marked PPFE features in approximately 10% of patients with idiopathic pulmonary fibrosis, 11% of patients with systemic sclerosis-associated ILD, 6.5% of patients with rheumatoid arthritis-associated ILD, and 23% of patients with hypersensitivity pneumonitis. Drug therapy has not been evaluated prospectively. A small retrospective study suggests that nintedanib may slow disease progression. However, whether the efficacy of antifibrotics is comparable in PPFE and in other forms of progressive pulmonary fibrosis warrants further evaluation.

SUMMARY

Accumulating data indicate that PPFE features are associated with poor prognosis in fibrosing ILDs. Further research on the management of PPFE is warranted.

Pulmonary hypertension or pulmonary arterial hypertension in idiopathic pleuroparenchymal fibroelastosis: An updated comprehensive review

Idiopathic pleuroparenchymal fibroelastosis (iPPFE) is a little-known entity with unique clinical, radiological, and pathological features. iPPFE is chronic interstitial pneumonia characterized by the thickening of elastic fibers in the pleura and subpleural parenchyma involving the upper lobes. Computed tomography pulmonary angiography (CTPA) usually depicts bilateral pleural thickening, with a left scalloped appearance that conditions retraction of the structures of the superior mediastinum and both pulmonary hila, associated with pulmonary consolidations with bronchogram air and thickening of the peribronchovascular interstitium, in addition to areas of left apical air trapping. When severe enough, the disease leads to progressive loss of volume of the upper lobes, decreased body mass, and platythorax. Some patients with iPPFE follow an inexorably progressive course culminating in irreversible respiratory failure and premature death. Up to 20% of patients might develop pulmonary hypertension (PH); transthoracic echocardiography is used as a screening test for PH; right heart catheterization performed in a tertiary-care hospital will confirm the diagnosis. Because iPPFE can be easily confused and misdiagnosed with infectious pathologies, such as pulmonary tuberculosis, and easily confuse physicians with little expertise in diffuse interstitial lung diseases, knowing the differential diagnoses, clinical presentation, imaging, and complications of the iPPFE allows for an early diagnosis and gives patients who suffer from it a better quality of life. This report presents a comprehensive review of PPFEi, discussing severe precapillary pulmonary hypertension and the associated findings demonstrated by right heart catheterization (RHC), which be of interest for cardiopulmonologists.

Pleuroparenchymal fibroelastosis in rheumatoid arthritis-associated interstitial lung disease

Background

Pleuroparenchymal fibroelastosis (PPFE) is a rare interstitial lung disease (ILD) featuring dense fibrosis of the visceral pleura and subpleural parenchyma, mostly in the upper lobes. PPFE can present in other ILDs, including rheumatoid arthritis-associated ILD (RA-ILD). The aim of this retrospective study was to investigate the prevalence and clinical implications of coexistent PPFE in RA-ILD.

Methods

Overall, 477 patients with RA-ILD were recruited from two cohorts; their clinical data and HRCT images were analysed. The criteria for diagnosing PPFE were (1) pleural thickening with bilateral subpleural dense fibrosis in the upper lobes, (2) evidence of disease progression, and (3) absence of other identifiable aetiologies.

Results

The median follow-up duration was 3.3 years. The mean age of the patients was 63.4 years, and 60.0% were women. PPFE was identified in 31 patients (6.5%). The PPFE group showed significantly lower body mass index and forced vital capacity (FVC) and more frequent usual interstitial pneumonia (UIP)-like pattern on HRCT than no-PPFE group. The risk factors for all-cause mortality were older age, lower FVC, and the presence of UIP-like pattern on HRCT; PPFE was not significantly associated with mortality in both all patients and a subgroup with a UIP-like pattern. The presence of PPFE was associated with a significantly increased risk of pneumothorax and greater decline in diffusing capacity.

Conclusions

PPFE was not rare in patients with RA-ILD and was significantly associated with an increased risk of pneumothorax and greater lung function decline, though we found no significant association with mortality.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02064-z.

Idiopathic Pulmonary Fibrosis (an Update) and Progressive Pulmonary Fibrosis in Adults: An Official ATS/ERS/JRS/ALAT Clinical Practice Guideline

Background: This American Thoracic Society, European Respiratory Society, Japanese Respiratory Society, and Asociación Latinoamericana de Tórax guideline updates prior idiopathic pulmonary fibrosis (IPF) guidelines and addresses the progression of pulmonary fibrosis in patients with interstitial lung diseases (ILDs) other than IPF. Methods: A committee was composed of multidisciplinary experts in ILD, methodologists, and patient representatives. 1) Update of IPF: Radiological and histopathological criteria for IPF were updated by consensus. Questions about transbronchial lung cryobiopsy, genomic classifier testing, antacid medication, and antireflux surgery were informed by systematic reviews and answered with evidence-based recommendations using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. 2) Progressive pulmonary fibrosis (PPF): PPF was defined, and then radiological and physiological criteria for PPF were determined by consensus. Questions about pirfenidone and nintedanib were informed by systematic reviews and answered with evidence-based recommendations using the GRADE approach. Results:1) Update of IPF: A conditional recommendation was made to regard transbronchial lung cryobiopsy as an acceptable alternative to surgical lung biopsy in centers with appropriate expertise. No recommendation was made for or against genomic classifier testing. Conditional recommendations were made against antacid medication and antireflux surgery for the treatment of IPF. 2) PPF: PPF was defined as at least two of three criteria (worsening symptoms, radiological progression, and physiological progression) occurring within the past year with no alternative explanation in a patient with an ILD other than IPF. A conditional recommendation was made for nintedanib, and additional research into pirfenidone was recommended. Conclusions: The conditional recommendations in this guideline are intended to provide the basis for rational, informed decisions by clinicians.

Radiological pleuroparenchymal fibroelastosis-like lesion in idiopathic interstitial pneumonias

Background

Pleuroparenchymal fibroelastosis (PPFE) is characterised by predominant upper lobe pleural and subpleural lung parenchymal fibrosis. Radiological PPFE-like lesion has been associated with various types of interstitial lung diseases. However, the prevalence and clinical significance of radiological PPFE-like lesion in patients with idiopathic interstitial pneumonias (IIPs) are not fully understood. We aimed to determine the prevalence and clinical impact on survival of radiological PPFE-like lesion in patients with IIPs.

Methods

A post-hoc analysis was conducted using data from the Japanese nationwide cloud-based database of patients with IIPs. All the patients in the database were diagnosed as having IIPs by multidisciplinary discussion. Patients diagnosed with idiopathic PPFE were excluded. Clinical data and chest computed tomography (CT) image of 419 patients with IIPs were analysed. The presence of radiological PPFE-like lesion was independently evaluated by two chest radiologists blind to the clinical data.

Results

Of the 419 patients with IIPs, radiological PPFE-like lesions were detected in 101 (24.1%) patients, mainly in idiopathic pulmonary fibrosis (IPF) and unclassifiable IIPs, but less in idiopathic nonspecific interstitial pneumonia. Prognostic analyses revealed that radiological PPFE-like lesion was significantly associated with poor outcome in patients with IIPs, which was independent of age, IPF diagnosis and %FVC. In survival analyses, the patients with radiological PPFE-like lesions had poor survival compared with those without (log-rank, p < 0.0001). Subgroup analyses demonstrated that radiological PPFE-like lesion was significantly associated with poor survival both in patients with IPF and those with unclassifiable IIPs.

Conclusion

Radiological PPFE-like lesion is a condition that could exist in IIPs, mainly in IPF and unclassifiable IIPs. Importantly, the radiological PPFE-like lesion is a non-invasive marker to predict poor outcome in patients with IIPs, which should be carefully considered in clinical practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01892-9.

Clinical, radiological, and pathological features of idiopathic and secondary interstitial pneumonia cases with pleuroparenchymal fibroelastosis undergoing lung transplantation

AIMS

Idiopathic pleuroparenchymal fibroelastosis (PPFE) is a rare type of idiopathic interstitial pneumonia, and pathological PPFE is also observed in secondary interstitial pneumonia. This study aimed to evaluate the pathological findings associated with radiological PPFE-like lesions and the clinical and morphological features of patients with pathological PPFE.

METHODS AND RESULTS

We retrospectively reviewed the pathology of the explanted lungs from 59 lung transplant recipients with radiological PPFE-like lesions. Pathological PPFE lesions were identified in 14 patients with idiopathic cases and 12 patients with secondary cases. Pathological PPFE was associated with previous pneumothorax, a volume loss in the upper lobes and a flattened chest. Patients with idiopathic and secondary cases with pathological PPFE had similar clinical, radiological, and pathological findings, while fibroblastic foci were more common in patients with idiopathic cases, and patients with secondary cases more frequently showed alveolar septal thickening with elastosis or fibrosis. Post-transplantation survival did not differ between patients with idiopathic and secondary cases with pathological PPFE (log-rank; P=0.57) and was similar between patients with idiopathic cases with pathological PPFE and patients with idiopathic pulmonary fibrosis (IPF) (log-rank; P = 0.62).

CONCLUSIONS

Not all patients with interstitial pneumonia with radiological PPFE-like lesions have pathological PPFE. Characteristic clinical features can suggest the presence of pathological PPFE, and idiopathic and secondary cases with pathological PPFE are similar except for fibroblastic foci in idiopathic cases and alveolar septal thickening with elastosis or fibrosis in secondary cases. Patients with pathological PPFE have a similar prognosis to those with IPF after transplantation.

Platythorax progresses with lung involvement in pleuroparenchymal fibroelastosis

BACKGROUND

Patients diagnosed with pleuroparenchymal fibroelastosis (PPFE) exhibit unique clinical features, including upper lobe-dominant lung involvement and platythorax (or flattened thoracic cage). Although platythorax have been shown to be a sign of disease progression, the temporal relationship between the progression of platythorax and the extent of lung involvement has not been closely investigated.

METHODS

We retrospectively investigated patients diagnosed with PPFE, who did not exhibit fibrotic lesions other than PPFE in the lower lobes. We estimated the fibrosis score, which is a visual score indicating the percentage of lung parenchyma occupied by the disease on computed tomography images selected every 2 cm from the lung apex to the lung base, and the flat chest index (the ratio of the anteroposterior diameter of the thoracic cage to the transverse diameter of the thoracic cage). Additionally, we investigated serial changes in the flat chest index and fibrosis score.

RESULTS

A total of 29 patients were included in this study. The fibrosis score was found to be weakly and inversely correlated with forced vital capacity %predicted at the diagnosis (r = -0.40, p = 0.038). Furthermore, the annual changes in the flat chest index and fibrosis score was found to be moderately and inversely correlated (r = -0.663, p = 0.0037).

CONCLUSIONS

These results indicate that there is a causal relationship between the progression of fibroelastosis and that of platythorax in patients with PPFE.

Nintedanib in idiopathic and secondary pleuroparenchymal fibroelastosis

Background

Pleuroparenchymal fibroelastosis (PPFE) has a variable disease course with dismal prognosis in the majority of patients with no validated drug therapy. This study is to evaluate the effect of nintedanib in patients with idiopathic and secondary PPFE. Patients admitted to a tertiary care center (2010–2019) were included into this retrospective analysis if they had a multidisciplinary diagnosis of PPFE, had been followed-up for 3 months or more, and had lung function tests and chest CTs available for review. Changes in pulmonary function tests were assessed using non-parametric tests and linear mixed effect model. Lung volumes were measured with lobar segmentation using chest CT.

Results

Out of 21 patients with PPFE, nine had received nintedanib, six had received another treatment and another six patients were monitored without drug therapy. Annual FVC (% of predicted) relative decline was − 13.6 ± 13.4%/year before nintedanib and − 1.6 ± 6.02%/year during nintedanib treatment (p = 0.014), whereas no significant change in FVC% relative decline was found in patients receiving another treatment (− 13.25 ± 34 before vs − 16.61 ± 36.2%/year during treatment; p = 0.343). Using linear mixed effect model, the slope in FVC was − 0.97%/month (95% CI: − 1.42; − 0.52) before treatment and − 0.50%/month (95% CI: − 0.88; 0.13) on nintedanib, with a difference between groups of + 0.47%/month (95% CI: 0.16; 0.78), p = 0.004. The decline in the upper lung volumes measured by CT was − 233 mL/year ± 387 mL/year before nintedanib and − 149 mL/year ± 173 mL/year on nintedanib (p = 0.327). Nintedanib tolerability was unremarkable.

Conclusion

In patients with PPFE, nintedanib treatment might be associated with slower decline in lung function, paving the way for prospective, controlled studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-02043-5.

Pleuroparenchymal fibroelastosis in idiopathic pulmonary fibrosis: Survival analysis using visual and computer-based computed tomography assessment

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) and pleuroparenchymal fibroelastosis (PPFE) are known to have poor outcomes but detailed examinations of prognostic significance of an association between these morphologic processes are lacking.

METHODS

Retrospective observational study of independent derivation and validation cohorts of IPF populations. Upper-lobe PPFE extent was scored visually (vPPFE) as categories of absent, moderate, marked. Computerised upper-zone PPFE extent (cPPFE) was examined continuously and using a threshold of 2·5% pleural surface area. vPPFE and cPPFE were evaluated against 1-year FVC decline (estimated using mixed-effects models) and mortality. Multivariable models were adjusted for age, gender, smoking history, antifibrotic treatment and diffusion capacity for carbon monoxide.

FINDINGS

PPFE prevalence was 49% (derivation cohort, n = 142) and 72% (validation cohort, n = 145). vPPFE marginally contributed 3-14% to variance in interstitial lung disease (ILD) severity across both cohorts.In multivariable models, marked vPPFE was independently associated with 1-year FVC decline (derivation: regression coefficient 18·3, 95 CI 8·47-28·2%; validation: 7·51, 1·85-13·2%) and mortality (derivation: hazard ratio [HR] 7·70, 95% CI 3·50-16·9; validation: HR 3·01, 1·33-6·81). Similarly, continuous and dichotomised cPPFE were associated with 1-year FVC decline and mortality (cPPFE ≥ 2·5% derivation: HR 5·26, 3·00-9·22; validation: HR 2·06, 1·28-3·31). Individuals with cPPFE ≥ 2·5% or marked vPPFE had the lowest median survival, the cPPFE threshold demonstrated greater discrimination of poor outcomes at two and three years than marked vPPFE.

INTERPRETATION

PPFE quantification supports distinction of IPF patients with a worse outcome independent of established ILD severity measures. This has the potential to improve prognostic management and elucidate separate pathways of disease progression.

FUNDING

This research was funded in whole or in part by the Wellcome Trust [209,553/Z/17/Z] and the NIHR UCLH Biomedical Research Centre, UK.

Prognostic role of KL-6 in SSc-ILD patients with pleuroparenchymal fibroelastosis

BACKGROUND

Krebs von den Lungen-6 (KL-6) is a high-molecular-weight (200kDa) glycoprotein proposed as a diagnostic biomarker for differentiating interstitial lung disease (ILD). Systemic sclerosis (SSc) is a rare immune-mediated disorder, and ILD is the leading cause of morbidity and mortality. Pleuroparenchymal fibroelastosis (PPFE) has been described to have a poor prognosis in SSc-ILD patients. This study undertook to compare serial changes in KL-6 in SSc-ILD patients with and without PPFE, to verify its prognostic value as a disease biomarker.

MATERIALS AND METHODS

Twenty-five SSc-ILD patients (median IQR, 62 (56-58); 20% males) were retrospectively enrolled. 12 SSc-ILD patients (48%) had also a radiological diagnosis of PPFE. Serum KL-6 concentrations were measured by KL-6 reagent assay (Fujirebio Europe, Ghent, Belgium).

RESULTS

Serum KL-6 measurements were increased in SSc-ILD patients with and without PPFE compared with healthy controls (P < .0001). Comparative analysis of the rate of variation of KL-6 over the 6 years of follow-up was performed by serial two-yearly KL-6 measurements: Δ1(t1-t0), Δ2(t2-t1) and Δ3(t3-t2). In SSc-ILD patients with PPFE pattern, Δ3 was significantly different than those without PPFE pattern (P = .0020). Serum KL-6 levels were significantly different (P = .0455) either at Δ2 and Δ3 in the PPFE group. In SSc-ILD patients with PPFE, at t3 serum KL-6 concentrations were inversely correlated with FEV1 (r = -.76; P = .037) and FVC percentages (r = -.79; P = .028).

CONCLUSION

These results suggest that serial measurements of KL-6 in the follow-up of these patients may help to monitor disease progression. In real life, in SSc-ILD patients PPFE should be always evaluated at CT and when present should suggest a tight follow-up to monitor its evolution.

A proposed prognostic prediction score for pleuroparenchymal fibroelastosis

BACKGROUND

Clinical course of pleuroparenchymal fibroelastosis (PPFE) shows considerable variation among patients, but there is no established prognostic prediction model for PPFE.

METHODS

The prediction model was developed using retrospective data from two cohorts: our single-center cohort and a nationwide multicenter cohort involving 21 institutions. Cox regression analyses were used to identify prognostic factors. The total score was defined as the weighted sum of values for the selected variables. The performance of the prediction models was evaluated by Harrell's concordance index (C-index). We also examined the usefulness of the gender-age-physiology (GAP) model for predicting the prognosis of PPFE patients.

RESULTS

We examined 104 patients with PPFE (52 cases from each cohort). In a multivariate Cox analysis, a lower forced vital capacity (FVC [defined as FVC < 65%]; hazard ratio [HR], 2.23), a history of pneumothorax (HR, 3.27), the presence of a lower lobe interstitial lung disease (ILD) (HR, 2.31), and higher serum Krebs von den Lungen-6 (KL-6) levels (> 550 U/mL, HR, 2.56) were significantly associated with a poor prognosis. The total score was calculated as 1 × (FVC, < 65%) + 1 × (history of pneumothorax) + 1 × (presence of lower lobe ILD) + 1 × (KL-6, > 550 U/mL). PPFE patients were divided into three groups based on the prognostic score: stage I (0-1 points), stage II (2 points), and stage III (3-4 points). The survival rates were significantly different in each stage. The GAP stage was significantly associated with the prognosis of PPFE, but no difference was found between moderate (stage II) and severe (stage III) disease. Our new model for PPFE patients (PPFE Prognosis Score) showed better performance in the prediction of mortality in comparison to the GAP model (C-index of 0.713 vs. 0.649).

CONCLUSIONS

Our new model for PPFE patients could be useful for predicting their prognosis.

Interstitial lung disease pathology in systemic sclerosis

Interstitial lung disease is a relatively frequent manifestation of systemic sclerosis with approximately one-third of patients developing clinical restrictive lung disease. Fibrotic nonspecific interstitial pneumonia is the most common cause of diffuse parenchymal lung disease in patients with systemic sclerosis-associated interstitial lung disease (SSc-ILD), followed by usual interstitial pneumonia (UIP). Radiographic pleuroparenchymal fibroelastosis-like changes may accompany other forms of interstitial lung disease, most commonly UIP. In an appropriate clinical setting with supportive high-resolution computed tomography findings, lung biopsy is not needed to confirm the presence of interstitial lung disease and surgical lung biopsies are often reserved for atypical presentations. In this review, we discuss the histological findings that define the most common patterns of SSc-ILD and outline other findings sometimes encountered in lung biopsies obtained from systemic sclerosis patients, including pulmonary vascular changes, aspiration, chronic pleuritis, and diffuse alveolar damage.

Asbestos exposure and tuberculous pleurisy as developmental causes of progressive unilateral upper-lung field pulmonary fibrosis radiologically consistent with pleuroparenchymal fibroelastosis

BACKGROUND

Unilateral upper-lung field pulmonary fibrosis (upper-PF), which is radiologically consistent with pleuroparenchymal fibroelastosis, develops after thoracic surgery. In most patients with unilateral upper-PF, aberrant intra-/extra thoracic air commonly emerges and an autopsy shows chronic pleuritis, which indicates that pleural involvement is associated with upper-PF development. If so, there may be patients with unilateral upper-PF who have a history of pleural involvement, including tuberculous pleurisy (TP) or asbestos exposure (AE). This study aimed to examine this supposition.

METHODS

We examined the radiological reports of all consecutive patients from 2012 to 2018 to investigate whether there were patients having unilateral upper-PF and a history of TP or AE.

RESULTS

Eight patients were included in the study. Five patients had a history of TP, and the remaining three had that of AE. All patients were men and had respiratory symptoms, and seven patients presented with restrictive ventilatory impairment. The interval between TP or last AE and upper-PF development was long, with a median of over 20 years. The upper-PF lesion was commonly located in the right lung, and aberrant intrathoracic air was observed in five patients during their clinical course. Additionally, the upper-PF lesion transformed into a cystic lesion in six patients, which resulted in Aspergillus infection in two patients. The prognosis was poor, with a median overall survival of 38 months.

CONCLUSIONS

Unilateral upper-PF developed even in patients with a history of pleural involvement. Our results indicate that pleural involvement plays an important role in the development of unilateral upper-PF.

A contemporary practical approach to the multidisciplinary management of unclassifiable interstitial lung disease

Fibrotic interstitial lung diseases (ILDs) frequently have nonspecific and overlapping clinical and radiological features, resulting in approximately 10-20% of patients with ILD lacking a clear diagnosis and thus being labelled with unclassifiable ILD. The objective of this review is to describe how patients with unclassifiable ILD should be evaluated and what impact specific clinical, radiological, and histopathological features may have on management decisions, focusing on patients with a predominantly fibrotic phenotype. We highlight recent data that have suggested an increasing role for antifibrotic medications in a variety of fibrotic ILDs, but justify the ongoing importance of making an accurate ILD diagnosis given the benefit of immunomodulatory therapies in many patient populations. We provide a practical approach to support management decisions that can be used by clinicians and tested by clinical researchers, and further identify the need for additional research to support a rational and standardised approach to the management of patients with unclassifiable ILD.

Pulmonary Fibroelastotic Remodelling Revisited

Pulmonary fibroelastotic remodelling occurs within a broad spectrum of diseases with vastly divergent outcomes. So far, no comprehensive terminology has been established to adequately address and distinguish histomorphological and clinical entities. We aimed to describe the range of fibroelastotic changes and define stringent histological criteria. Furthermore, we wanted to clarify the corresponding terminology in order to distinguish clinically relevant variants of pulmonary fibroelastotic remodelling. We revisited pulmonary specimens with fibroelastotic remodelling sampled during the last ten years at a large European lung transplant centre. Consensus-based definitions of specific variants of fibroelastotic changes were developed on the basis of well-defined cases and applied. Systematic evaluation was performed in a steps-wise algorithm, first identifying the fulcrum of the respective lesions, and then assessing the morphological changes, their distribution and the features of the adjacent parenchyma. We defined typical alveolar fibro-elastosis as collagenous effacement of the alveolar spaces with accompanying hyper-elastosis of the remodelled and paucicellular alveolar walls, independent of the underlying disease in 45 cases. Clinically, this pattern could be seen in (idiopathic) pleuroparenchymal fibro-elastosis, interstitial lung disease with concomitant alveolar fibro-elastosis, following hematopoietic stem cell and lung transplantation, autoimmune disease, radio-/chemotherapy, and pulmonary apical caps. Novel in-transit and activity stages of fibroelastotic remodelling were identified. For the first time, we present a comprehensive definition of fibroelastotic remodelling, its anatomic distribution, and clinical associations, thereby providing a basis for stringent patient stratification and prediction of outcome.

HRCT Diagnosis of Pleuroparenchymal fibroelastosis: Report of two cases

Pleuroparenchymal fibroelastosis (PPFE) is a rare idiopathic interstitial pneumonia that is often underdiagnosed on computed tomography scans. The disease process involves a combination of fibrosis involving the visceral pleura and fibroelastic changes within the subpleural lung parenchyma. Although definitive diagnosis is based on pathological evaluation, this is often not feasible and pattern recognition on CT as "definite PPFE" or "consistent with PPFE" is important given that sub group of patients will undergo rapid progression with clinical deterioration.

Pleuroparenchymal fibroelastosis: Clinical, radiological and histopathological features

Pleuroparenchymal fibroelastosis (PPFE) is a rare, generally idiopathic form of interstitial pneumonia with unique clinical, radiological and histopathological features. It is named after the presence of upper lobe pleural and subjacent parenchymal fibrosis, with accompanying elastic fibers. Although it is usually an idiopathic disease, it has been linked to other co-existent diseases. Diagnostic suspicion of PPFE is based on the identification of typical abnormalities on chest CT scan, which are prevailingly located in the upper lobes, adjacent to the apex of the lungs. Diagnosis can be confirmed by histological analysis, although biopsy is not always feasible. The disease is generally progressive, but not uniformly. The course of the disease is frequently slow and involves a progressive loss of upper lobe volume, which results in platythorax, associated with a significant reduction of body mass. PPFE concomitant to other interstitial lung diseases is associated with a poorer prognosis. The disease occasionally progresses rapidly causing irreversible respiratory insufficiency, which leads to death. Currently, there is no effective pharmacological therapy available, and lung transplantation is the best therapeutic option. The purpose of this review is to draw the attention to PPFE, describe its clinical, radiological and histopathological features, analyze its diagnostic criteria, and provide an update on the management of the disease.

Prognostic and Clinical Value of Cluster Analysis in Idiopathic Pleuroparenchymal Fibroelastosis Phenotypes

Idiopathic pleuroparenchymal fibroelastosis (PPFE) is a distinctive interstitial pneumonia with upper lobe predominance that shows unique morphological features among idiopathic interstitial pneumonias (IIPs). Affected patients have a variety of clinical presentations with heterogeneous clinical courses. Cluster analysis is a valuable tool for identifying distinct clinical phenotypes under heterogeneous conditions. This study aimed to identify the phenotypes of patients with idiopathic PPFE. Using cluster analysis, novel PPFE phenotypes were identified among subjects from our multicenter cohort, and outcomes were stratified according to phenotypic clusters. Among the subjects with baseline data (N = 84), four clusters were identified. Cluster 1 included younger male subjects with coexisting non-UIP-like patterns. Cluster 2 included elderly female nonsmokers with low body mass index (BMI). Cluster 3 included elderly male smokers with a coexisting IP-like pattern. Cluster 4 included younger male smokers without lower lobe lesions. Patients in cluster 3 had significantly worse survival outcomes than those in clusters 1, 2, and 4 (p < 0.001, p = 0.0041, and p = 0.0155, respectively). Among idiopathic PPFE patients, cluster analysis using baseline characteristics identified four distinct clinical phenotypes that might predict survival outcomes.

Lung Transplantation for Pleuroparenchymal Fibroelastosis

Pleuroparenchymal fibroelastosis (PPFE), a new disease entity associated with interstitial pneumonia, is characterized by fibrosis and elastosis involving the pleura and subpleural lung parenchyma, predominantly in the upper lobe. As the awareness of this disease entity has increased, many studies have revealed the prevalence and incidence, clinical and pathological characteristics, and disease course of PPFE. Patients with PPFE reportedly have several unique clinical characteristics—including an extremely low body mass index with a slender body and chest wall deformity, known as “flat chest”. As this disease progresses, shrinking of the lungs often causes life-threatening complications, such as pneumothorax, and associated air leak syndrome. Lung transplantation is considered the only effective treatment for patients with advanced PPFE; however, little is known about the influences of the characteristics of PPFE on the outcome of lung transplantation. This review focuses on the unique clinicopathologic characteristics of PPFE and associated outcomes of lung transplantation for these patients.

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

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.

Treatment with antifibrotic agents in idiopathic pleuroparenchymal fibroelastosis with usual interstitial pneumonia

Background

There are no established therapeutic options available for idiopathic pleuroparenchymal fibroelastosis (IPPFE) apart from supportive care and lung transplantation. Furthermore, it is known that IPPFE with a usual interstitial pneumonia (UIP) pattern and lower lobe predominance is a disease entity distinct from idiopathic pulmonary fibrosis (IPF). To our knowledge, few studies are available that report on the efficacy of antifibrotic agents for IPPFE with UIP.

Aim

The aim of this study was to compare the efficacy of antifibrotic agents between IPPFE with UIP and typical IPF in real-world clinical practice.

Patients and methods

A retrospective analysis was performed on the medical records of all patients at two interstitial lung disease centres. Sixty-four patients were diagnosed as having IPPFE with UIP and 195 patients were diagnosed with typical IPF. We compared the efficacy of antifibrotic agents between these two groups.

Results

Survival time was significantly shorter in the patients with IPPFE with UIP. Some 125 patients were administered antifibrotic agents for over 6 months (34 with IPPFE with UIP and 91 with typical IPF). Reduced forced vital capacity (FVC) 6 months after treatment with antifibrotic agents was significantly greater in the IPPFE with UIP group than in those in the typical IPF group. Moreover, the change in % predicted FVC was significantly greater during the follow-up in patients with IPPFE with UIP compared with those with typical IPF.

Conclusions

The efficacy of antifibrotic agents was limited in patients with IPPFE with UIP. Thus, IPPFE with UIP remains a fatal and progressive disease.

This study demonstrated that patients with IPPFE with UIP have a poorer prognosis than those with typical IPF because these patients were intractable to treatment with antifibrotic agentshttps://bit.ly/38LbAKD

Alveolar Epithelial Denudation Is a Major Factor in the Pathogenesis of Pleuroparenchymal Fibroelastosis

The pathogenesis of pleuroparenchymal fibroelastosis (PPFE), a rare interstitial lung disease, remains unclear. Based on previous reports and our experience, we hypothesized that alveolar epithelial denudation (AED) was involved in the pathogenesis of PPFE. This multicenter retrospective study investigated the percentage of AED and the features of the denudated areas in 26 PPFE cases, 30 idiopathic pulmonary fibrosis (IPF) cases, and 29 controls. PPFE patients had lower forced vital capacities and higher residual volume/total lung capacities in pulmonary function tests compared to IPF and control patients. Histopathologically, subpleural fibroelastosis was observed in PPFE, and AED was observed in 12.01% of cases in the subpleural or interlobular septa regardless of fibroelastosis. The percentage of AED in the PPFE group was significantly higher than that in the IPF group (6.84%; p = 0.03) and the normal group (1.19%; p < 0.001). In the IPF group, the percentage of AED and the presence of PPFE-like lesions in the upper lobes were examined radiologically, but no correlation was found. We showed that AED frequently occurred in PPFE. AED was less frequent in IPF, which, in combination with imaging data, suggests that PPFE may have a different pathogenesis from IPF.

Comparison of Clinical Characteristics and Outcomes between Idiopathic and Secondary Pleuroparenchymal Fibroelastosis

Background: Pleuroparenchymal fibroelastosis (PPFE) is a unique clinical, radiologic, and histopathologic entity for which several potential etiologies have been reported recently. However, there has been no comprehensive study of secondary PPFE. Objective: Assessment of the clinical characteristics, outcomes, and prognostic factors of secondary and idiopathic PPFE. Methods: We retrospectively reviewed the medical records of consecutive PPFE patients between January 1999 and December 2018. We identified 132 idiopathic PPFE patients and 32 secondary PPFE patients. Results: The incidence of interstitial lung disease (ILD) pattern different from the usual interstitial pneumonia (UIP) pattern in the lower lobes was higher in secondary PPFE patients (38.5%) than in idiopathic PPFE patients (61.5%, p = 0.02). The idiopathic and secondary PPFE groups did not differ significantly in terms of laboratory data, respiratory complications, and survival (median: 5.0 years vs. 4.1 years, p = 0.95). The presence of UIP pattern was independently associated with increased mortality in multivariate analyses in idiopathic PPFE patients, but not in secondary PPFE patients. Conclusions: The frequency and prognostic impact of UIP-pattern ILD differed between idiopathic and secondary PPFE patients. Lung transplantation should be considered in secondary PPFE patients with low diffusing capacity of the lungs for carbon monoxide (DLCO) regardless of lower-lobe ILD pattern.

Pleuroparenchymal fibroelastosis in Mycobacterium avium complex pulmonary disease: clinical characteristics and prognostic impact

The association between Mycobacterium avium complex pulmonary disease (MAC-PD) and pleuroparenchymal fibroelastosis (PPFE) has been reported previously, and interstitial pneumonia as a comorbidity is associated with a worse prognosis. However, no study has thoroughly reported on PPFE associated with MAC-PD. The present study investigated the prevalence, clinical characteristics, and prognostic impact of PPFE in patients with MAC-PD. A total of 224 patients, newly diagnosed with MAC-PD, were retrospectively reviewed. At the time of diagnosis, chest high-resolution computed tomography (HRCT), sputum examination, and clinical characteristics were collected. The extent of PPFE and MAC-PD was evaluated semi-quantitatively using HRCT scores. Risk factor analysis for clinical or radiological deterioration necessitating multidrug antimicrobial treatment within 3 years, and all-cause mortality within 5 years, from the initial diagnosis was performed based on the PPFE score. PPFE was observed in 59 out of 224 patients (26.3%). A higher PPFE score was a risk factor for dyspnoea, fatigue, and lower body mass index (BMI) (p<0.05). Although PPFE score did not correlate with clinical or radiological deterioration within 3 years (p=0.576), a higher PPFE score (adjusted OR 1.66, 95% CI 1.06-2.60, p=0.028) and lower BMI (adjusted OR 0.61, 95% CI 0.39-0.94, p=0.028) increased the risk of 5-year mortality. PPFE is a relatively common complication and an independent poor prognostic factor of MAC-PD. This study highlights the need for further studies investigating whether the presence of PPFE can be a clinical indicator for initiating treatment of MAC-PD.

Pleuroparenchymal fibroelastosis in rheumatic autoimmune diseases: a systematic literature review

OBJECTIVES

Pleuroparenchymal fibroelastosis (PPFE) is characterized by predominantly upper lobe pleural and subjacent parenchymal fibrosis; PPFE features were described in patients with rheumatic autoimmune diseases (RAID). A systematic literature review was performed to investigate the prevalence, prognosis and potential association of PPFE with previous immunosuppression in RAID.

METHODS

EMBASE, Web of Science and PubMed databases were questioned from inception to 1 September 2019. Articles published in English and addressing PPFE in patients with RAID were selected.

RESULTS

Twenty out of 794 papers were selected with a total of 76 cases of RAID-PPFE patients (20 SSc, 9 RA, 6 IIM6 primary SS, 5 overlap syndromes, 3 ANCA-associated vasculitides, 2 granulomatosis with polyangiitis, 1 microscopic polyangiitis, 1 UCTD, 1 SLE, 1 GCA and 21 patients with non-specified RAID). Dyspnoea was the most frequently reported symptom (37/48 patients, 77%). Patients frequently presented with a restrictive pattern and decline in diffusing lung capacity for carbon monoxide. During the follow-up, 7/12 patients had progression at imaging, 22/39 presented a generic clinical worsening, 19/38 had a functional deterioration and 15/43 remained stable.

CONCLUSION

The present systematic literature review confirms that PPFE features are present in RAID. Rheumatologists should be aware of this new radiological pattern that holds a bad prognosis.

Pneumothorax in Patients with Idiopathic Pleuroparenchymal Fibroelastosis: Incidence, Clinical Features, and Risk Factors

BACKGROUND

Idiopathic pleuroparenchymal fibroelastosis (PPFE) is a rare form of idiopathic interstitial pneumonia that is characterized by predominantly upper lobe pleural and subpleural lung parenchymal fibrosis. Pneumothorax is one of the major respiratory complications in PPFE patients; however, its clinical features are poorly understood.

OBJECTIVE

We aimed to investigate the complication of pneumothorax in patients with idiopathic PPFE.

METHODS

A retrospective multicenter study involving 89 patients who had been diagnosed with idiopathic PPFE was conducted. We investigated the cumulative incidence, clinical features, and risk factors of pneumothorax after the diagnosis of idiopathic PPFE.

RESULTS

Pneumothorax developed in 53 patients (59.6%) with 120 events during the observation period (41.8 ± 35.0 months). The cumulative incidence of pneumothorax was 24.8, 44.9, and 53.9% at 1, 2, and 3 years, respectively. Most events of pneumothorax were asymptomatic (n = 85; 70.8%) and small in size (n = 92; 76.7%); 30 patients (56.6%) had recurrent pneumothorax. Chest drainage was required in 23 pneumothorax events (19.2%), and a persistent air leak was observed in 13 (56.5%). Patients with pneumothorax were predominantly male and frequently had pathological diagnoses of PPFE and prior history of pneumothorax and corticosteroid use; they also had significantly poorer survival than those without pneumothorax (log-rank test; p = 0.001). Multivariate analysis revealed that a higher residual volume/total lung capacity ratio was significantly associated with the development of pneumothorax after the diagnosis.

CONCLUSION

Pneumothorax is often asymptomatic and recurrent in patients with idiopathic PPFE, leading to poor outcomes in some cases.

The pathogenesis and pathology of idiopathic pleuroparenchymal fibroelastosis

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is a rare subtype of idiopathic interstitial pneumonias that consists of elastofibrosis involving the lung parenchyma and pleural collagenous fibrosis predominantly located in the upper lobes. IPPFE has various distinct clinical and physiological characteristics, including platythorax and a marked decrease of forced vital capacity with an increased residual volume on a respiratory function test. The concept of IPPFE is now widely recognized and some diagnostic criteria have been proposed. In addition, the accumulation of cases has revealed the pathological features of IPPFE. However, little is known about the pathogenesis or the process of disease formation in IPPFE. This review article will provide a summary of the pathological features and previously reported hypotheses on disease formation in IPPFE, to discuss the potential etiologies and pathogenesis of IPPFE.

Pleuroparenchymal fibroelastosis-like lesions in patients with interstitial pneumonia diagnosed by multidisciplinary discussion with surgical lung biopsy

Purpose

The present study aimed to evaluate the significance of Pleuroparenchymal fibroelastosis (PPFE)-like lesions in predicting prognosis in patients with chronic interstitial pneumonia (IP).

Method

The present study enrolled 207 patients with IP in whom surgical lung biopsy was performed. Among the patients enrolled in the present study, 77 had idiopathic pulmonary fibrosis (IPF), 15 had nonspecific interstitial pneumonia (NSIP), 13 had chronic hypersensitivity pneumonitis (CHP), 41 had connective tissue disease (CTD), three had PPFE, and 58 had unclassifiable diagnosis. The incidence, characteristics, and thickness of PPFE-like lesions were evaluated in each patient with IP. Additionally, the influence of PPFE-like lesions on the prognosis was also determined.

Results

Of 207 patients, 160 (77.3 %) showed PPFE-like lesions. The frequency of PPFE-like lesions was similar in patients with IPF, NSIP, CHP, CTD, and unclassifiable diagnosis (79.5 %, 79.5 %, 73.2 %, 65.9 %, and 81 %, respectively); however, PPFE-like lesions were present in all patients with PPFE (p = 0.42). Consequently, there was no significant difference in the characteristics of PPFE-like lesions among patients with all forms of IP, except PPFE. PPFE-like lesions were not a significant predictor of prognosis (hazard ratio [HR], 1.16; 95 % confidence interval [CI], 0.64–2.10, p = 0.62); however, patients with PPFE-like lesions under the aortic arch had significantly poorer prognoses (HR, 2.70; 95 % CI, 1.66–4.39, p < 0.001). For craniocaudal extent comparison, patients with IPF with PPFE-like lesions below the level of the carina had significantly poorer prognoses than those without PPFE-like lesions (p = 0.001, overall survival 53.1 and 80.6, respectively).

Conclusion

PPFE-like lesions are common in patients with IP, and their characteristics were not significantly different among all forms of IP, except idiopathic PPFE. The broad extent of PPFE-like lesions is an important predictor of prognosis in patients with IPF.

Pleuroparenchymal fibroelastosis (PPFE)-like finding on CT in daily practice -prevalence and serial changes

Objective

To characterize the prevalence of PPFE (pleuroparenchymal fibroelastosis)-like finding on CT in daily practice and to identify the risk factors for its progression.

Matelials & methods

2416 consecutive daily CT examinations were screened for PPFE-like finding. CT images with PPFE-like finding were retrospectively reviewed for the extent, maximum height, presence or absence of intraalveolar fibroelastosis (IAFE), emphysema, interstitial lung disease (ILD), suprasternal depression at the level of clavicle end, and bronchiectasis in upper lobe, and anterior-posterior/transverse diameter ratio (AT ratio) of thoracic cage. Serial CT scans more than 3 years before the baseline scan were also reviewed and compared when available.

Results

380 patients (median age of 65, M:F = 153:227) were recognized as having PPFE-like finding. The lowest level of PPFE-like finding was T5 in median, horizontal extent was 0–25 % in 229/380, 25–50 % in 66 and >50 % in 24. Median height was 8.0 mm. IAFE was seen in 75, emphysema in 71, ILD in 59, chronic bronchial disorder in 71, suprasternal depression in 148, upper-lobe bronchial dilatation in 124. Mean AT ratio was 0.63. Serial images were available in 131 patients. 11 showed significant progression, 57 showed mild progression. Existing ILD lesion and >25 % horizontal extent were significantly related to significant progression.

Conclusions

PPFE-like finding was seen relatively in high proportion. Extensive lesion in axial plane and co-existing ILD might be risk factors of progression.

Physiological Criteria Are Useful for the Diagnosis of Idiopathic Pleuroparenchymal Fibroelastosis

BACKGROUND

Diagnostic criteria of idiopathic pleuroparenchymal fibroelastosis (IPPFE) were recently proposed, including physiological criteria of the body mass index (BMI) and percentage of the predicted values of residual volume (RV)/total lung capacity (TLC) (RV/TLC %pred.). The aim of this study was to evaluate (i) whether the physiologic criteria are useful for the diagnosis and (ii) whether the flat chest index, defined as the ratio of the anteroposterior diameter to the transverse diameter of the thoracic cage, could be an alternative parameter to RV/TLC %pred.

METHODS

We selected consecutive IPPFE patients and idiopathic pulmonary fibrosis (IPF) patients. We examined the diagnostic sensitivity and specificity of the physiological criteria and flat chest index for differentiating IPPFE patients from IPF patients.

RESULTS

This study included 37 IPPFE patients and 89 IPF patients. The physiological criteria distinguished IPPFE patients from IPF patients with a sensitivity of 78.6% and specificity of 88.0%. The combination of the flat chest index and BMI was also effective for differentiation (sensitivity of 82.1% and specificity of 89.3%).

CONCLUSION

We verified the good performance of the physiologic criteria in a different cohort. When the RV/TLC is not measured, using the flat chest index instead of RV/TLC %pred. may be reasonable.

Extent of pulmonary fibrosis on high-resolution computed tomography is a prognostic factor in patients with pleuroparenchymal fibroelastosis

BACKGROUND

Several prognostic factors for pleuroparenchymal fibroelastosis (PPFE) have recently been reported. However, detailed high-resolution computed tomography (HRCT) findings have not yet been evaluated as prognostic factors. This study retrospectively investigated whether HRCT findings are prognostic factors in patients with PPFE compared to those with idiopathic pulmonary fibrosis (IPF).

METHODS

Patients with PPFE and IPF diagnosed at our hospital between January 2008 and December 2016 were enrolled. Clinical and HRCT characteristics were obtained. In addition to our patients, we also analyzed data of PPFE patients whose cause of death had been identified in previous studies.

RESULTS

We enrolled 15 patients with PPFE and 75 patients with IPF. Consolidation and maximum pleural thickening were significantly higher in patients with PPFE than in those with IPF (both P < .001). Fibrosis score, honeycomb area, and traction bronchiectasis were not significantly different between these patient groups but were significant prognostic factors in patients with PPFE in univariate analysis (P = .021, P = .017, and P = .014, respectively). The proportions of deaths by acute exacerbation or lung cancer were significantly lower in patients with PPFE than in those with IPF (P < .001 and P = .001, respectively), whereas death by respiratory failure was significantly more frequent in PPFE patients (P < .001).

CONCLUSIONS

HRCT findings, such as fibrosis score, honeycomb area, and traction bronchiectasis, were independent prognostic factors in patients with PPFE. Respiratory failure, but not acute exacerbation and lung cancer, was the main cause of death in patients with PPFE.

Acute Exacerbation of Pleuroparenchymal Fibroelastosis Secondary to Allogenic Hematopoietic Stem Cell Transplantation

In this article, we report a case with pleuroparenchymal fibroelastosis (PPFE) following hematopoietic stem cell transplantation (HSCT) that developed acute respiratory failure with new bilateral ground glass opacity, which could not be explained by either a pulmonary infection, drug toxicity or extraparenchymal causes. Although combination therapy with multiple immunosuppressants was transiently effective, the patient died from a recurrent exacerbation. Autopsied lungs demonstrated diffuse alveolar damage superimposed on PPFE. There was no evidence of any coexisting interstitial pneumonia with the usual interstitial pneumonia (UIP) pattern. Our case suggests that acute exacerbation can occur in patients with post-HSCT PPFE, even when a coexisting UIP pattern is absent.

Effectiveness of pirfenidone for idiopathic pulmonary fibrosis associated with pleuroparenchymal fibroelastosis-like lesions and nonspecific interstitial pneumonia

BACKGROUND

Pirfenidone treatment can slow decline in forced vital capacity (FVC) in idiopathic pulmonary fibrosis (IPF). However, its effects for usual interstitial pneumonia (UIP) with pleuroparenchymal fibroelastosis-like lesions (UIP+PPFELL) and UIP with nonspecific interstitial pneumonia (UIP+NSIP) are unclear.

OBJECTIVES

The aim of study is to assess pirfenidone effectiveness for UIP+PPFELL and UIP+NSIP.

METHODS

We retrospectively analysed data from 58 IPF patients treated with pirfenidone more than 6 months. The outcomes of interest were 6-month follow-up pulmonary function test results, progression-free survival (PFS) and overall survival (OS). Treatment was considered effective if FVC decline was <5% during the 6-month period. We compared clinical characteristics, effectiveness, PFS and OS between patients with typical IPF (n = 32), UIP+PPFELL (n = 12) and UIP+NSIP (n = 14).

RESULTS

Data from 58 IPF patients were analysed. At the 6-month follow-up examination, treatment was deemed effective for 9 of 14 (64%) UIP+NSIP patients, 6 of 12 (50%) UIP+PPFELL patients and 14 of 32 (44%) patients with typical IPF. The 6-month decline in FVC before treatment was greater than that after starting treatment in the UIP+NSIP (-210 vs. -57 mL; P = 0.09), UIP+PPFELL (-370 vs. -89 mL; P = 0.001) and typical IPF (-172 vs. -85 mL; P = 0.37). PFS did not significantly differ between the three groups. OS was significantly shorter for UIP+PPFELL (312 days) than for UIP+NSIP (545 days) and typical IPF (661 days).

CONCLUSIONS

Pirfenidone decreased the decline in FVC in patients with UIP+PPFELL and UIP+NSIP, as well as in those with typical IPF. However, outcomes were worse for patients with UIP+PPFELL.

A case report of idiopathic pleuroparenchymal fibroelastosis with severe respiratory failure in pregnancy

Background

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is a rare lung disease that manifests as parenchymal fibrosis of the upper lung lobe and pleura. There have been no reports of IPPFE complicating pregnancy. Here, we report a case of IPPFE that deteriorated rapidly during pregnancy.

Case presentation

A 29-year-old woman presented with dyspnea and dry cough at 19 weeks of gestation. IPPFE with acute exacerbation was suspected on chest computed tomography (CT). Despite steroid treatment, her condition progressed. A cesarean section was performed at 28 weeks of gestation. On postoperative day 26, she underwent living-donor lung transplantation. She was discharged a year after transplantation.

Conclusion

Our experience suggested that when pregnancy is complicated by PPFE, the disease may deteriorate rapidly. In this case, even though IPPFE with acute exacerbation was diagnosed during pregnancy, live birth was achieved, and the mother survived after lung transplantation. Lung transplantation should be considered in these patients because, once advanced, pulmonary lesions may be irreversible.

Pleuroparenchymal fibroelastosis in patients with idiopathic pulmonary fibrosis

BACKGROUND AND OBJECTIVE

PPFE is characterized by fibrosis in the pleura and subpleural lung parenchyma in the upper lobes, while other types of ILD, mainly UIP, can be observed in about half of the patients in their lower lobes. The aim of this study was to evaluate the clinical significance of the radiologically defined PPFE in patients with IPF.

METHODS

Clinical data and chest CT images were retrospectively analysed in 445 patients with IPF (biopsy-proven cases, n = 165). The radiological criteria of PPFE were defined as follows: (i) bilateral subpleural dense fibrosis with or without pleural thickening in the upper lobes, (ii) evidence of disease progression and (iii) no clinical evidence of identifiable aetiologies.

RESULTS

The median follow-up period was 43.0 months. The mean age of the patients was 66.4 years and 76.4% were male. PPFE was identified in 28 patients (6.3%). The PPFE group showed lower BMI and lung function (FVC and TLC) at baseline, more frequent pneumothorax and pneumomediastinum, higher decline rates in lung function and poorer prognosis during follow-up than the no-PPFE group. PPFE was an independent risk factor (HR = 2.953, 95% CI: 1.350-6.460, P = 0.007) for pneumothorax or pneumomediastinum, but not for mortality in patients with IPF.

CONCLUSION

Among patients with IPF, the PPFE group, when compared to the no-PPFE group, showed lower BMI and lung function and showed more frequent complications and poorer survival during follow-up.