Quantitative analysis of lung elastic fibers in idiopathic pleuroparenchymal fibroelastosis (IPPFE): comparison of clinical, radiological, and pathological findings with those of idiopathic pulmonary fibrosis (IPF)

Relationship between idiopathic interstitial pneumonias (IIPs) and connective tissue disease-related interstitial lung disease (CTD-ILD): A narrative review

While idiopathic interstitial pneumonia (IIP) centering on idiopathic pulmonary fibrosis (IPF) is the most prevalent interstitial lung disease (ILD), especially in the older adult population, connective tissue disease (CTD)-related ILD is the second most prevalent ILD. The pathogenesis of IPF is primarily fibrosis, whereas that of other ILDs, particularly CTD-ILD, is mainly inflammation. Therefore, a precise diagnosis is crucial for selecting appropriate treatments, such as antifibrotic or immunosuppressive agents. In addition, some patients with IIP have CTD-related features, such as arthritis and skin eruption, but do not meet the criteria for any CTD, this is referred to as interstitial pneumonia with autoimmune features (IPAF). IPAF is closely associated with idiopathic nonspecific interstitial pneumonia (iNSIP) and cryptogenic organizing pneumonia (COP). Furthermore, patients with iNSIP or those with NSIP with OP overlap frequently develop polymyositis/dermatomyositis after the diagnosis of IIP. Acute exacerbation of ILD, the most common cause of death, occurs more frequently in patients with IPF than in those with other ILDs. Although acute exacerbation of CTD-ILD occurs at a low rate of incidence, patients with rheumatoid arthritis, microscopic polyangiitis, or systemic sclerosis experience more acute exacerbation of CTD-ILD than those with other CTD. In this review, the features of each IIP, focusing on CTD-related signatures, are summarized, and the pathogenesis and appropriate treatments to improve the prognoses of patients with various ILDs are discussed.

Multidisciplinary Approach to the Diagnosis of Idiopathic Interstitial Pneumonias: Focus on the Pathologist's Key Role

Idiopathic Interstitial Pneumonias (IIPs) are a heterogeneous group of the broader category of Interstitial Lung Diseases (ILDs), pathologically characterized by the distortion of lung parenchyma by interstitial inflammation and/or fibrosis. The American Thoracic Society (ATS)/European Respiratory Society (ERS) international multidisciplinary consensus classification of the IIPs was published in 2002 and then updated in 2013, with the authors emphasizing the need for a multidisciplinary approach to the diagnosis of IIPs. The histological evaluation of IIPs is challenging, and different types of IIPs are classically associated with specific histopathological patterns. However, morphological overlaps can be observed, and the same histopathological features can be seen in totally different clinical settings. Therefore, the pathologist's aim is to recognize the pathologic-morphologic pattern of disease in this clinical setting, and only after multi-disciplinary evaluation, if there is concordance between clinical and radiological findings, a definitive diagnosis of specific IIP can be established, allowing the optimal clinical-therapeutic management of the patient.

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 after hematopoietic stem cell transplantation in children: a propensity score-matched analysis

OBJECTIVES

To investigate the incidence, risk factors, and clinical outcomes of pleuroparenchymal fibroelastosis (PPFE) in pediatric hematopoietic stem cell transplantation (HSCT) recipients.

METHODS

This single-center, retrospective, case-control study included 738 consecutive patients who underwent chest CT more than 3 months after HSCT. We identified patients who fulfilled the diagnostic criteria for PPFE and assessed their clinical characteristics and radiologic findings. Propensity score-matched analysis was performed using four covariates (age, sex, HSCT type, and primary disease). The risk factors and clinical outcomes of PPFE were analyzed using the Fine and Gray regression model and stratified log-rank test in the matched groups.

RESULTS

PPFE was identified in 4% (31/738, 8.3 ± 3.1 years, 15 males) of the pediatric HSCT recipients with a median time of 2.7 years after HSCT, and it occurred following allogeneic (5%, 15/317), autologous (4%, 15/379), or both (2%, 1/42). Matching yielded 30 and 130 cases in the PPFE and control groups, respectively. The PPFE group showed more frequent late-onset noninfectious pulmonary complications (LONIPCs) and pneumonia more than 3 months after HSCT (p < 0.05). Multivariable analysis showed a significantly higher risk of PPFE in HSCT recipients who had pneumonia more than 3 months after HSCT (hazard ratio = 10.78 [95% confidence interval: 4.29, 27.13], p < 0.001). The PPFE group showed higher mortality (73%, 22/30) and poorer median overall survival (6.8 years [95% confidence interval: 4.1, 9.5]) than the control group (p < 0.001).

CONCLUSIONS

PPFE represents a severe type of LONIPC after HSCT. HSCT recipients with pneumonia after HSCT may have an increased risk of PPFE.

KEY POINTS

• The incidence of pleuroparenchymal fibroelastosis is not negligible (4%), and it can occur after either allogeneic or autologous hematopoietic stem cell transplantation. • Pleuroparenchymal fibroelastosis after hematopoietic stem cell transplantation showed poor outcome with a high mortality rate of 73% and median overall survival of 6.8 years. • After hematopoietic stem cell transplantation, pneumonia may increase the risk of pleuroparenchymal fibroelastosis development in children. • Lung biopsy should not be indicated in patients with pleuroparenchymal fibroelastosis findings on chest CT as it can cause refractory pneumothorax without helping the diagnosis.

Serum S100A8 and S100A9 as prognostic biomarkers in acute exacerbation of idiopathic pulmonary fibrosis

BACKGROUND

Acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) is a devastating and life-threatening condition during its clinical course. Biomarkers for precisely anticipating the prognosis of AE-IPF remain to be fully established. The objective of this study was to clarify whether S100A8 and S100A9, which are calcium-binding proteins mainly produced by activated neutrophils, are significant prognostic biomarkers in AE-IPF.

METHODS

Thirty-seven patients with AE-IPF who were diagnosed and treated at our hospital were retrospectively evaluated. The serum levels of S100A8 and S100A9 were measured using enzyme-linked immunosorbent assay, and the relationships between these levels and clinical parameters or prognosis were evaluated.

RESULTS

The serum levels of S100A8 (median 386.5 ng/mL) and S100A9 (median 60.2 ng/mL) in patients with AE-IPF were significantly higher than those in age-matched healthy controls and in patients at IPF diagnosis (p < 0.001 for all combinations). The serum levels of S100A8 negatively correlated with percent forced vital capacity (r = -0.356, p = 0.049) and positively correlated with peripheral white blood cell number (r = 0.509, p = 0.002). Immunohistochemical staining of autopsy lung specimens showed that neutrophils, present mainly in the alveolar septum, were positive for S100A8 and S100A9. Patients with AE-IPF with higher levels of S100A8 or S100A9 showed significantly worse 3-month survival than those with lower levels (log-rank test, both p = 0.028). Finally, in multivariate analysis, the serum levels of both S100A8 and S100A9 were significant prognostic factors (hazard ratio 4.032, p = 0.023 and hazard ratio 4.327, p = 0.012).

CONCLUSION

The serum levels of S100A8 and S100A9 at AE were significant prognostic biomarkers in patients with AE-IPF.

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.

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.

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.

Transbronchial cryobiopsy for diagnosis of pleuroparenchymal fibroelastosis

Rationale

Pleuroparenchymal fibroelastosis (PPFE) is a rare subtype of idiopathic interstitial pneumonias. PPFE mostly affects the upper lung zones and is characterized radiologically by pleural and subpleural fibrotic thickening with a reticular pattern. There is no established treatment for PPFE but lung transplantation can be considered for advanced stage. The gold standard for the diagnosis of PPFE is surgical lung biopsy (SLB) but the bronchoscopic transbronchial cryobiopsy (TBCB) is a less invasive alternative.

Patient concerns

We report here two cases in which the diagnosis of PPFE was established with the help of TBCB.

Diagnosis and interventions

Bronchoscopy with TBCB was performed under sedation with spontaneous ventilation and the help of an uncuffed ET tube.

Outcomes

Histopathology showed intra-alveolar fibroblastic proliferation with elastosis, which confirmed the diagnosis of PPFE.

Lessons

The current report demonstrates that TBCB can be a useful and safe tool to confirm the diagnosis of PPFE. According to our knowledge, this is one of few reports that shows successful diagnosis of PPFE by TBCB.

Serum latent transforming growth factor-β binding protein 4 as a novel biomarker for idiopathic pleuroparenchymal fibroelastosis

BACKGROUND

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is a rare idiopathic interstitial pneumonia characterized by an upper lobe-dominant interstitial increase in predominantly elastic fibers. The accumulation of cases has resulted in a refinement of the disease concept, but there are no blood biomarkers to aid in the diagnosis or prediction of a progressive phenotype among PPFE patients. Several organizers, including latent transforming growth factor-β binding protein 4 (LTBP-4), are known to be involved in elastogenesis. However, the potential of LTBP-4 as a blood biomarker for PPFE has not been investigated.

METHODS

We selected cases of clinically or histologically diagnosed IPPFE (n = 20) along with idiopathic pulmonary fibrosis (IPF) patients (n = 39) and healthy controls (n = 10). We quantified the protein levels of LTBP-4 in lung tissues and serum samples.

RESULTS

The LTBP-4 levels in lung tissue of PPFE patients were 2.16 times higher than those of IPF patients (p = 0.032). The serum concentration of LTBP-4 (pg/ml) in IPPFE was higher than that in healthy controls (1429 [154-3620] vs. 187 [56.4-490], p = 0.013). The serum concentration of LTBP-4 in IPPFE was markedly higher than that in IPF without a significant difference (1429 [154-3620] vs. 915 [491-1967], p = 0.671). In addition, a higher concentration of LTBP-4 was associated with a poor prognosis in IPPFE patients.

CONCLUSIONS

The serum concentration of LTBP-4 may aid in the diagnosis of IPPFE or the prediction of an aggressive phenotype.

Pathology of Idiopathic Interstitial Pneumonias

This review discusses diagnostic pathology in idiopathic interstitial pneumonias (IIPs). Accurate understanding of basic structure of lung lobules is critical because the location of abnormalities inside the lobule is an important effector of pathology diagnosis. Depending on the method of obtaining tissue, recognition of the location may be difficult or impossible. Cryobiopsy is a new technology and its coverage of lung lobules is limited. This article discusses fundamental anatomy and approach to interstitial pneumonia. In addition, most histologic types of IIPs are covered, but the focus is on diagnosis of usual interstitial pneumonia because of its clinical importance.

Analysis of serum adiponectin and leptin in patients with acute exacerbation of idiopathic pulmonary fibrosis

Weight loss progresses with the progression of idiopathic pulmonary fibrosis (IPF), and acute exacerbation of IPF (AE-IPF) frequently occurs in its advanced stage. Adiponectin and leptin are adipokines produced from adipose tissue, and are related to thinness and obesity, respectively. Additionally, these adipokines are implicated in the regulation of inflammation and fibrosis centering on peroxisome proliferator-activated receptor γ (PPARγ). However, the relationship between adiponectin/leptin and AE-IPF remains poorly known. We conducted this study to evaluate levels of serum adiponectin/leptin, and to elucidate the clinical importance of adiponectin and leptin in patients with AE-IPF. Thirty-two patients (39 episodes) who were diagnosed with AE-IPF at our hospital from 1997 to 2016 were retrospectively studied. Serum adiponectin and leptin concentrations were measured with enzyme-linked immunosorbent assay. Patients with AE-IPF showed higher levels of serum adiponectin and leptin than those at initial diagnosis of IPF (p = 0.007 and p = 0.027, respectively). Serum adiponectin/leptin (A/L) ratio was negatively correlated with body mass index at AE-IPF (r = -0.456, p = 0.003) and PaO₂ before AE-IPF (r = -0.498, p = 0.034), and positively correlated with C-reactive protein at AE-IPF (r = 0.316, p = 0.049). Patients with higher A/L ratios had worse survival than those with lower A/L ratios (log-rank, p = 0.026). Further, in multivariate analysis, serum A/L ratio was a significant prognostic factor in patients with AE-IPF (HR 2.60, p = 0.042). In conclusion, the higher adiponectin/leptin ratio may be associated with a poor prognosis in patients with AE-IPF.

Pleuroparenchymal fibroelastosis secondary to autologous hematopoietic stem cell transplantation: A case report

Pleuroparenchymal fibroelastosis (PPFE) is a rare interstitial lung disease. Although an increased number of PPFE cases have been reported recently, the characteristics of this condition have not been well described. The present study reports on the case of a 34-year-old male patient who presented with unilateral lung abnormalities. The patient was admitted due to a 9-year history of progressive cough and exertional dyspnea, as well as a history of Hodgkin's lymphoma treated by autologous hematopoietic stem cell transplantation (HSCT). The patient had been initially diagnosed with tuberculosis and received regular anti-tuberculosis therapy for 18 months; however, the symptoms progressed. Serial chest computed tomography scans indicated a gradually worsening diffuse pleural thickening, dense subpleural opacification and volume loss, associated with evidence of fibrosis in the right lung. On physical examination the patient was cachectic, with a body mass index of 18.5 kg/m², and he had a flattened thoracic cage. Arterial blood gas analysis revealed hypoxia. Pulmonary function tests revealed restrictive ventilation dysfunction and decreased diffusion capacity. The microbiological and cytological examinations were negative. Lung biopsy revealed a thickened pleura consisting of large amounts of collagen and elastic fibers, coexisting with subpleural intra-alveolar fibrosis with alveolar septal elastosis, without inflammatory infiltrates. The patient was diagnosed with PPFE secondary to HSCT and eventually succumbed to respiratory failure and infection while waiting for a lung transplant. Physicians should be aware of the typical and atypical characteristics of this rare disease, as its clinical and radiological characteristics may lead to misdiagnosis, particularly as chronic infections. The prognosis remains poor without effective long-term treatment.

Reduced area of the normal lung on high-resolution computed tomography predicts poor survival in patients with lung cancer and combined pulmonary fibrosis and emphysema

BACKGROUND

This study aimed to determine the radiologic predictors and clarify the clinical features related to survival in patients with combined pulmonary fibrosis and emphysema (CPFE) and lung cancer.

METHODS

We retrospectively reviewed the medical chart data and high-resolution computed tomography (HRCT) findings for 81 consecutive patients with CPFE and 92 primary lung cancers (70 men, 11 women; mean age, 70.9 years). We selected 8 axial HRCT images per patient, and visually determined the normal lung, modified Goddard, and fibrosis scores. Multivariate analysis was performed using the Cox proportional hazards regression model.

RESULTS

The major clinical features were a high smoking index of 54.8 pack-years and idiopathic pulmonary fibrosis (n = 44). The major lung cancer profile was a peripherally located squamous cell carcinoma (n = 40) or adenocarcinoma (n = 31) adjacent to emphysema in the upper/middle lobe (n = 27) or fibrosis in the lower lobe (n = 26). The median total normal lung, modified Goddard, and fibrosis scores were 10, 8, and 8, respectively. TNM Classification of malignant tumors (TNM) stage I, II, III, and IV was noted in 37, 7, 26, and 22 patients, respectively. Acute exacerbation occurred in 20 patients. Multivariate analysis showed that a higher normal lung score and TNM stage were independent radiologic and clinical predictors of poor survival at the time of diagnosis of lung cancer.

CONCLUSIONS

A markedly reduced area of normal lung on HRCT was a relevant radiologic predictor of survival.

Pleuroparenchymal fibroelastosis as a histological background of autoimmune diseases

Patients with autoimmune disease-related interstitial lung disease (AID-ILD) occasionally develop radiologic pleuroparenchymal fibroelastosis (PPFE)-like lesions. However, the significance of AID as an etiology of PPFE has not been fully elucidated. The aim of this study is to verify the increase of elastic fibers in AID-ILD patients and evaluate the prevalence of histological PPFE in patients with AID-ILD. We selected cases of clinically diagnosed AID-ILD and idiopathic pulmonary fibrosis (IPF), in which an autopsy had been performed or in which the patient had undergone pneumonectomy for lung transplantation. We quantified the collagen fibers and elastic fibers in each lobe as the percentage of the non-aerated lung area (collagen fiber score and elastic fiber score, respectively) in histological specimens from a total of 73 patients (AID-ILD, n = 24; IPF, n = 49). There were no significant differences in the collagen fiber scores of the AID-ILD and IPF groups. Meanwhile, the elastic fiber scores of the AID-ILD group were significantly greater than those of the IPF group in the whole lung (17.3 ± 7.70 vs 11.6 ± 4.55), and the upper (16.6 ± 8.11 vs 11.2 ± 5.18), and lower (18.0 ± 9.68 vs 12.0 ± 5.55) lobes (all p < 0.01). Histological PPFE pattern was found in 12 of 24 AID-ILD patients (50%), and histological PPFE pattern as a dominant pattern of fibrosis was found in 2 of the 24 patients (8%). Thus, PPFE can be a manifestation of AID-ILD.

A CARE-compliant case report: Lung transplantation for a Chinese young man with idiopathic pleuroparenchymal fibroelastosis

RATIONAL

Pleuroparenchymal fibroelastosis (PPFE) is a rare interstitial lung disease that is characterized radiologically by apical pleural thickening and histologically by elastic fibrosis of the visceral pleura. Although PPFE cases have been reported occasionally since this disease was initially described, most such cases have involved secondary PPFE. Idiopathic PPFE (iPPFE) cases have been less thoroughly studied. There are no effective medications for patients with iPPFE.

PATIENT CONCERNS

A 34-year-old man with no asbestos or cigarette exposure was admitted to our ward due to worsening cough and exertional dyspnea for 10 years. He had a "flattened thoracic cage" and bibasilar inspiratory crackles without finger clubbing. A series of chest computed tomography scans during the preceding 10 years revealed the presence of gradual, exaggerated, upper lung-predominant, diffuse pleural thickening and dense subpleural opacification with traction bronchiectasis.

DIAGNOSIS

He was performed with video-assisted thoracic surgical (VATS) lung biopsy. The pulmonary histopathologic examination showed thickened visceral pleura and prominent subpleural fibroelastosis, confirming the diagnosis of iPPFE.

INTERVENTION

After the failure of treatment with prednisone plus cyclophosphamide and sequential pirfenidone administration, he was arranged with bilateral lung transplantation two years later.

OUTCOMES

The patient did not require supplemental oxygenation anymore after he recovered from lung transplantation.

LESSONS

Bilateral lung transplantation might be tried for the end-stage iPPFE cases.

Body Mass Index and arterial blood oxygenation as prognostic factors in patients with idiopathic pleuroparenchymal fibroelastosis

Background: Idiopathic pleuroparenchymal fibroelastosis (IPPFE) was recently proposed as an entity to be included among rare idiopathic interstitial pneumonias (IIPs). However, the cause, clinical features and prognosis of this rare entity have not been elucidated. Objectives: We aimed to examine the clinical features, outcomes and prognostic factors for IPPFE in comparison to those of idiopathic pulmonary fibrosis (IPF). Methods: We retrospectively analyzed 20 patients with IPPFE and 71 with IPF. We compared clinical features, blood examination data, and respiratory functions at the time of diagnosis. Results: The IPPFE group had a significantly lower body mass index (BMI), percent forced vital capacity (%FVC), total lung capacity (%TLC) and expiratory reserve volume (%ERV), as well as a higher residual volume to TLC (RV/TLC) ratio than the IPF group. The annual FVC changes in the IPPFE group (-326ml/year) were significantly larger than those in the IPF group (-142ml/year). Survival was significantly poorer in the IPPFE than in the IPF group (P = 0.021). BMI and the partial pressure of oxygen in arterial blood (PaO₂) were significantly related to the outcome of IPPFE. Conclusions: Our present results indicate the prognosis of IPPFE patients to be poorer than that of IPF patients. We advocate that BMI and arterial blood PaO₂ be determined at the first visit as these parameters are closely related to patients' outcomes. Prospective evaluation of IPPFE starting in the subclinical phase is necessary to assure that appropriate measures are taken before progression. (Sarcoidosis Vasc Diffuse Lung Dis 2017; 34: 35-40).

Incidental Paratracheal Air Cysts on Thoracic CT and Their Association with Chronic Inflammatory Lung Disease

Purpose. To determine the association between the progression of upper lung fibrosis and paratracheal air cysts (PACs) size. Materials and Methods. The thoracic CT images of 4573 patients were reviewed for the prevalence, size, and location of PACs and their communication with trachea. In addition, the presence of upper lung fibrosis, emphysema, and bronchiectasis was evaluated in patients with PACs and compared with a control group without PACs. Upper lung fibrosis was analyzed using a fibrosis score system. Results. The prevalence of PACs was 6.8%. Communication with tracheal lumen was demonstrated by 31.5% of patients with PACs. The prevalence of fibrosis, emphysema, and bronchiectasis in patients with PACs were 67.5%, 21.9%, and 28.3%, respectively. The prevalence of fibrosis was significantly different in the two groups by univariable and multivariable analysis (odds ratio = 2.077, P < 0.001). 140 patients with fibrosis among PAC group underwent a previous or follow-up CT; the prevalence with increase in PAC sizes was higher in patients with increase in fibrosis score than those without it (66.2% versus 17.3%, P < 0.001). Conclusions. PACs appear to be highly related to upper lung fibrosis and moderately related to bronchiectasis. In patients with fibrosis, PAC sizes tended to increase with the progression of upper lung fibrosis.

Idiopathic Pleuroparenchymal Fibroelastosis

Purpose of the review

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is a rare fibrosing lung disease, affecting the visceral pleura and the subpleural parenchyma with an upper lobe predilection, included as a distinct clinicopathologic entity in the latest international multidisciplinary classification of the idiopathic interstitial pneumonias (IIP). We aim to summarize the current evidence on IPPFE, in terms of clinical features and potential treatments.

Recent findings

Overall, there is increasing awareness of PPFE in association with a separate ILD pattern. Although an agreed consensus on diagnosis has yet to be defined, a list of radiological and histopathological criteria has been proposed. Due to the unfavorable risk-benefit profile of surgical lung biopsy in a significant proportion of patients, a potential role for transbronchial lung cryobiopsy has been suggested. At present, lung transplantation remains the only curative option.

Summary

The increasing awareness of this condition among specialists has led to more frequent identification of IPPFE. Large international studies are needed to better characterize pathogenesis and pheno/endotypes of disease, a key step towards the development of effective treatments.

Chronic Cough and Bilateral Pneumothoraces in a Nonsmoker

An 82-year-old Japanese nonsmoking man presented with persistent dry cough and small left apical pneumothorax. High resolution CT scan of the chest demonstrated bilateral upper lobe pleuroparenchymal thickening and architectural distortion. Serial imaging revealed mild progression and development of small bilateral pneumothoraces, and pneumomediastinum. A surgical lung biopsy was required to confirm the diagnosis.

Idiopathic pleuroparenchymal fibroelastosis - A rare idiopathic interstitial pneumonia

Idiopathic pleuroparenchymal fibroelastosis is a rare idiopathic interstitial pneumonia. It was first described in 2004 and subsequently included in the ATS/ERS classification of idiopathic interstitial pneumonia in 2013. There have been few cases reported so far. The diagnostic criteria is still emerging and its etiology is being questioned. We report a case of pleuroparenchymal fibroelastosis probably idiopathic, the first of its kind to be reported from India, and a brief review of the literature.

Pathology of Idiopathic Interstitial Pneumonias

The updated classification of idiopathic interstitial pneumonias (IIPs) in 2013 by American Thoracic Society/European Respiratory Society included several important revisions to the categories described in the 2002 classification. In the updated classification, lymphoid interstitial pneumonia (LIP) was moved from major to rare IIPs, pleuroparenchymal fibroelastosis (PPFE) was newly included in the rare IIPs, acute fibrinous and organizing pneumonia (AFOP) and interstitial pneumonias with a bronchiolocentric distribution are recognized as rare histologic patterns, and unclassifiable IIP (UCIP) was classified as an IIP. However, recent reports indicate the areas of concern that may require further evaluation. Here, we describe the histopathologic features of the updated IIPs and their rare histologic patterns and also point out some of the issues to be considered in this context.

Idiopathic pleuroparenchymal fibroelastosis, a new idiopathic interstitial pneumonia: A case report

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is a rare disease, idiopathic in most of the cases described in the literature. We report the case of a 55-year-old patient, non-smoker with tuberculosis treated in his youth, starting with progressive dyspnoea and cough, with radiographic abnormalities consisting of pleural thickening, bronchiectasis and structural distortion predominantly in the upper lobes. Due to functional impairment and persistent radiographic abnormalities, biopsy by video-assisted thoracoscopic surgical was decided. The presence of striking elastosis, absence of interstitial damage and abrupt boundary of the fibrous lesion with healthy lung allowed the diagnosis of IPPFE. Currently, the patient has no specific treatment and is in follow-up in the Transplant Unit.

A Patient with Idiopathic Pleuroparenchymal Fibroelastosis Showing a Sustained Pulmonary Function due to Treatment with Pirfenidone

The patient was a 68-year-old man presenting with body weight loss and exertional dyspnea. High-resolution computed tomography of the chest showed dense subpleural consolidation with traction bronchiectasis and volume loss predominantly in bilateral apical lesions and upper lobes. A histopathological analysis of a specimen of the right upper lobe showed histological patterns which were consistent with idiopathic pleuroparenchymal fibroelastotis (IPPFE). Treatment with pirfenidone was introduced with the expectation of its potential benefit. The effect of pirfenidone was satisfactory, and a decline in forced vital capacity was inhibited during treatment. This is the first case report suggesting the efficacy of pirfenidone for patients with IPPFE.

RNA interference targeting carbohydrate sulfotransferase 3 diminishes macrophage accumulation, inhibits MMP-9 expression and promotes lung recovery in murine pulmonary emphysema

BACKGROUND

Chondroitin sulfate proteoglycans are an important mediators in inflammation and leukocyte trafficking. However, their roles in pulmonary emphysema have not been explored. In a murine model of elastase-induced pulmonary emphysema, we found increased carbohydrate sulfotransferase 3 (CHST3), a specific enzyme that synthesizes chondroitin 6-sulfate proteoglycan (C6SPG). To elucidate the role of C6SPG, we investigated the effect of small interfering RNA (siRNA) targeting CHST3 that inhibits C6SPG-synthesis on the pathogenesis of pulmonary emphysema.

METHODS

Mice were intraperitoneally injected with CHST3 siRNA or negative control siRNA on day0 and 7 after intratracheal instillation of elastase. Histology, respiratory function, glycosaminoglycans (GAGs) content, bronchoalveolar lavage (BAL), elastin staining and gene expressions of tumor necrosis factor (TNF)-α and matrix metalloproteinase (MMP)-9 mRNA were evaluated on day7 and/or day21.

RESULTS

CHST3 mRNA increased at day 7 and decreased thereafter in lung. CHST3 siRNA successfully inhibited the expression of CHST3 mRNA throughout the study and this was associated with significant reduction of GAGs and C6SPG. Airway destruction and respiratory function were improved by the treatment with CHST3 siRNA. CHST3 siRNA reduced the number of macrophages both in BAL and lung parenchyma and also suppressed the increased expressions of TNF-α and MMP-9 mRNA. Futhermore, CHST3 siRNA improved the reduction of the elastin in the alveolar walls.

CONCLUSIONS

CHST3 siRNA diminishes accumulation of excessive macrophages and the mediators, leading to accelerate the functional recovery from airway damage by repair of the elastin network associated with pulmonary emphysema.

Pleuroparenchymal fibroelastosis: Distinct pulmonary physiological features in nine patients

BACKGROUND

Pleuroparenchymal fibroelastosis (PPFE) is a rare idiopathic interstitial pneumonia defined by pleural and subpleural parenchymal fibrosis predominantly in the upper lobes. Although the radiological and pathological characteristics of PPFE have become increasingly recognized, its pulmonary physiological features are not well understood.

METHODS

We reviewed nine patients with radiologically and histologically proven PPFE, and evaluated pulmonary physiological data.

RESULTS

Of the nine patients, six were male and three were female. The median age at presentation was 61 years. Common symptoms were dyspnea on exertion, weight loss, and nonproductive cough. Recurrent pneumothorax was found in eight patients and pneumonia in four. Median pulmonary function test results were as follows: forced vital capacity, 55.4% predicted; total lung capacity (TLC), 67.1% predicted; residual volume (RV), 102.3% predicted; and RV/TLC, 143.6% predicted. RV/TLC was increased without evidence of small airway disease according to clinico-radiologic-pathologic evaluation. The median partial pressure of oxygen in arterial blood and the alveolar-arterial gradient of oxygen were within normal limits, although there was a slightly elevated partial pressure of carbon dioxide in arterial blood (PaCO2). PPFE progressed in all patients despite treatment with pirfenidone, corticosteroids, and immunosuppressive agents. Seven patients died during the follow-up, five because of hypercapnic respiratory failure.

CONCLUSIONS

PPFE is characterized by severe mechanical restriction with high RV/TLC, causing increased PaCO2 and eventual hypercapnic respiratory failure. These physiological findings may be useful as an adjunct in the diagnosis of PPFE.

Histological evolution of pleuroparenchymal fibroelastosis

AIMS

To investigate the histological evolution in the development of pleuroparenchymal fibroelastosis (PPFE).

METHODS AND RESULTS

We examined four patients who had undergone surgical lung biopsy twice, or who had undergone surgical lung biopsy and had been autopsied, and in whom the histological diagnosis of the first biopsy was not PPFE, but the diagnosis of the second biopsy or of the autopsy was PPFE. The histological patterns of the first biopsy were cellular and fibrotic interstitial pneumonia, cellular interstitial pneumonia (CIP) with organizing pneumonia, CIP with granulomas and acute lung injury in cases 1, 2, 3, and 4, respectively. Septal elastosis was already present in the non-specific interstitial pneumonia-like histology of case 1, but a few additional years were necessary to reach consolidated subpleural fibroelastosis. In case 3, subpleural fibroelastosis was already present in the first biopsy, but only to a small extent. Twelve years later, it was replaced by a long band of fibroelastosis. The septal inflammation and fibrosis and airspace organization observed in the first biopsies were replaced by less cellular subpleural fibroelastosis within 3-12 years.

CONCLUSIONS

Interstitial inflammation or acute lung injury may be an initial step in the development of PPFE.