Computed tomography findings of current nonspecific interstitial pneumonia based on the 2013 updated classification of idiopathic interstitial pneumonias: What is a characteristic of previously diagnosed nonspecific interstitial pneumonia excluded from the updated classification.

PURPOSE: To evaluate computed tomography (CT) findings of nonspecific interstitial pneumonia (NSIP) based on the current classification of idiopathic interstitial pneumonias (IIPs) and elucidate a characteristic of previously diagnosed NSIP excluded from the current classification. MATERIALS AND METHODS: The study included 74 patients with biopsy-proven NSIP (idiopathic NSIP [I-NSIP], 39 patients; NSIP associated with connective tissue disease [CTD-NSIP], 35 patients). Among patients who were compatible with the current classification of IIPs, 29 and 21 were categorized as having current I-NSIP and current CTD-NSIP, respectively. The remaining 24 patients were categorized as having previous I-NSIP or previous CTD-NSIP due to the primary pathologic diagnosis of cellular NSIP or associated findings of acute inflammatory changes. CT findings were evaluated and compared among the four groups. RESULTS: Current I-NSIP was indicated by ground-glass attenuation and reticulation with traction bronchiectasis/bronchiolectasis in predominantly peribronchovascular areas of the lower lung zone. The previous I-NSIP group tended to show broader airspace consolidation than the current I-NSIP group (p = 0.068). The previous CTD-NSIP group showed significantly broader airspace consolidation than the current I-NSIP group (p = 0.035). CONCLUSION: Broad airspace consolidation is a characteristic of previously diagnosed CTD-NSIP excluded from the current classification of IIPs.

The significance of multidisciplinary classifications based on transbronchial pathology in possible idiopathic interstitial pneumonias.

Surgical lung biopsy is regarded as the golden standard for the diagnosis of idiopathic interstitial pneumonias (IIPs). Here, we attempted to show the diagnostic accuracy of multidisciplinary classifications based on transbronchial pathology including transbronchial lung cryobiopsy (TBLC) , bronchoalveolar lavage fluid (BALF) and endobronchial ultrasound-guided transbronchial needle aspiration biopsy (EBUS-TBNA).Patients with suspected interstitial lung diseases admitted from June 1, 2016 to December 31, 2018 were involved. Patients with known causes of interstitial lung diseases and typical idiopathic pulmonary fibrosis diagnosed through clinical, radiological information were excluded. Patients with atypical idiopathic pulmonary fibrosis and possible IIPs accepted transbronchial pathological evaluation. Initial multidisciplinary diagnosis (MDD) classifications were made depending on clinical, radiological and transbronchial pathological information by a multidisciplinary team (MDT). The final MDD classifications were confirmed by subsequent therapeutic effects. All patients were followed up for at least 6 months.A total of 70 patients were finally involved. The samples of lung parenchyma extracted through TBLC were enough for confirmation of pathological diagnoses in 68.6% (48/70) cases. Samples of 6 cases were extracted by EBUS-TBNA. Bacteriological diagnoses were positive in 1 case by BALF. Pathological diagnoses of 77.1% (54/70) cases were achieved through TBLC, EBUS-TBNA and BALF. During the follow up study, the pulmonary lesions of 60% patients were improved, 11.43% were relapsed when glucocorticoid was reduced to small dose or withdrawal, 14.29% were leveled off and 8.57% were progressed. The diagnoses of 4 patients with progressed clinical feature were revised. As a result, 94.3% initial MDD classifications based on transbronchial pathology were consistent with the final MDD, and the difference of diagnostic yield wasn't significant between initial and final MDD (Z = -1.414, P = .157).Classifications of IIPs based on transbronchial pathology were useful and quite agreed with final MDD.

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.

Clinico-radio-pathological characteristics of unclassifiable idiopathic interstitial pneumonias.

BACKGROUND: The purpose of this study was to clarify the clinico-radio-pathological characteristics and prognostic factors of unclassifiable-idiopathic interstitial pneumonias (U-IIPs) diagnosed by surgical lung biopsy. METHODS: Among 86 patients with interstitial pneumonia who underwent surgical lung biopsy from January 2005 to September 2013, 33 (38.4%; 16 male patients; mean age, 64.4 ± 8.8 years) were diagnosed with U-IIPs. They were subsequently categorized into rapidly progressive (n = 7), slowly progressive (n = 7), and stable (n = 19) groups based on the decrease of the percent predicted forced vital capacity or percent predicted diffusing capacity of the lung carbon monoxide and the occurrence of acute exacerbation. The clinico-radio-pathological features and survival rates of the patients who were followed up for at least 3 years were examined. These cases were reevaluated retrospectively by multidisciplinary discussion. RESULTS: The rapidly progressive group had a significantly poorer prognosis than that of the other groups (p < 0.0001). Although there were no significant pattern differences on the chest high-resolution computed tomography, the fibrosis scores were significantly higher in the rapidly progressive group (p = 0.002). Furthermore, the percentage of fibroblastic foci assessed by the pathological analysis was also significantly higher in the rapidly progressive group (p = 0.006). Nine (27.3%) patients developed connective tissue diseases during follow-up. CONCLUSIONS: The radiologic patterns were not significantly different among the three clinical U-IIPs subgroups. Nevertheless, our findings suggested that the fibrosis scores and the percentage of fibroblastic foci could provide a prognostic assessment in U-IIPs.

Classification of idiopathic interstitial pneumonias using anti-myxovirus resistance-protein 1 autoantibody.

Chronic fibrosing idiopathic interstitial pneumonia (IIP) can be divided into two main types: idiopathic pulmonary fibrosis (IPF), a steroid-resistant and progressive disease with a median survival of 2-3 years, and idiopathic non-specific interstitial pneumonia (INSIP), a steroid-sensitive and non-progressive autoimmune disease. Although the clinical courses of these two diseases differ, they may be difficult to distinguish at diagnosis. We performed a comprehensive analysis of serum autoantibodies from patients definitively diagnosed with IPF, INSIP, autoimmune pulmonary alveolar proteinosis, and sarcoidosis. We identified disease-specific autoantibodies and enriched KEGG pathways unique to each disease, and demonstrated that IPF and INSIP are serologically distinct. Furthermore, we discovered a new INSIP-specific autoantibody, anti-myxovirus resistance-1 (MX1) autoantibody. Patients positive for anti-MX1 autoantibody constituted 17.5% of all cases of chronic fibrosing IIPs. Notably, patients rarely simultaneously carried the anti-MX1 autoantibody and the anti-aminoacyl-transfer RNA synthetase autoantibody, which is common in chronic fibrosing IIPs. Because MX1 is one of the most important interferon-inducible anti-viral genes, we have not only identified a new diagnostic autoantibody of INSIP but also obtained new insight into the pathology of INSIP, which may be associated with viral infection and autoimmunity.

[Idiopathic interstitial pneumonias in 2016]. / Actualités dans les pneumopathies interstitielles idiopathiques en 2016.

Idiopathic interstitial pneumonias comprise 8 clinicopathological entities, most of them with a chronic course and various prognosis. Idiopathic pulmonary fibrosis is the most frequent and most severe of these. Computed tomography has an important role for its diagnosis. It can identify the corresponding pathological pattern of usual interstitial pneumonia in about 50 percent of cases. It can suggest differential diagnosis in other cases, most frequently fibrosing nonspecific interstitial pneumonia and chronic hypersensitivity pneumonitis. Imaging features should be integrated to clinical and available pathologic data during multidisciplinary team meetings involving physicians with a good knowledge of interstitial diseases. Some cases may be unclassifiable, but these could later be reclassified as new data may occur or imaging features may change. Surgical lung biopsy is being less frequently performed and an emerging less invasive technique, lung cryobiopsy, is under evaluation. Pleuroparenchymal fibroelastosis is a distinct entity only recently described, with uncertain prevalence and prognosis that seems being quite often associated to another pattern of interstitial pneumonia.

Rare idiopathic interstitial pneumonias: LIP and PPFE and rare histologic patterns of interstitial pneumonias: AFOP and BPIP.

In the 2013 reclassification of the idiopathic interstitial pneumonias (IIPs), two rare IIPs (idiopathic lymphoid interstitial pneumonia (LIP), idiopathic pleuroparenchymal fibroelastosis (IPPFE)) and two rare histologic patterns (acute fibrinous and organizing pneumonia (AFOP), bronchiolocentric pattern of interstitial pneumonia (BPIP)) are described. All these entities are rare with small series published to date, mostly containing primary and secondary forms of disease. LIP is histologically characterized by diffuse polyclonal lymphoid cell infiltrate surrounding the airways and expanding the interstitium. Thin-walled cysts and diffuse ground glass are considered the typical radiologic features. The clinical course is highly variable with corticosteroid responsiveness evident in approximately half of cases. IPPFE is defined histologically by coexisting upper lobe pleural and intra-alveolar fibrosis with elastosis. Dense subpleural irregular fibrosis and consolidation are the cardinal radiologic features. A history of recurrent lower respiratory tract infection is frequent. Responses to immunomodulation have not been reported and the rate of progression appears to be highly variable. AFOP is a rare histologic pattern lying within the spectrum of acute/subacute lung injury, characterized by organizing pneumonia and intra-alveolar fibrin deposition without hyaline membranes. BPIP is characterized histologically by fibrosis and/or inflammation confined to the alveolar interstitium around bronchovascular bundles, overlapping with peribronchial metaplasia and fibrosis in some series. Currently, AFOP and BPIP are both best viewed as histological entities rather than true clinical disorders, in the absence of characteristic associated imaging patterns and clinical features.

American Thoracic Society-European Respiratory Society Classification of the Idiopathic Interstitial Pneumonias: Advances in Knowledge since 2002.

In the updated American Thoracic Society-European Respiratory Society classification of the idiopathic interstitial pneumonias (IIPs), the major entities have been preserved and grouped into (a) "chronic fibrosing IIPs" (idiopathic pulmonary fibrosis and idiopathic nonspecific interstitial pneumonia), (b) "smoking-related IIPs" (respiratory bronchiolitis-associated interstitial lung disease and desquamative interstitial pneumonia), (c) "acute or subacute IIPs" (cryptogenic organizing pneumonia and acute interstitial pneumonia), and (d) "rare IIPs" (lymphoid interstitial pneumonia and idiopathic pleuroparenchymal fibroelastosis). Furthermore, it has been acknowledged that a final diagnosis is not always achievable, and the category "unclassifiable IIP" has been proposed. The diagnostic interpretation of the IIPs is often challenging because other diseases with a known etiology (most notably, connective tissue disease and hypersensitivity pneumonitis) may show similar morphologic patterns. Indeed, more emphasis has been given to the integration of clinical, computed tomographic (CT), and pathologic findings for multidisciplinary diagnosis. Typical CT-based morphologic patterns are associated with the IIPs, and radiologists play an important role in diagnosis and characterization. Optimal CT quality and a systematic approach are both pivotal for evaluation of IIP. Interobserver variation for the various patterns encountered in the IIPs is an issue. It is important for radiologists to understand the longitudinal behavior of IIPs at serial CT examinations, especially for providing a framework for cases that are unclassifiable or in which a histologic diagnosis cannot be obtained.

Challenges in the classification of fibrotic ILD.

According to current international guidelines the idiopathic interstitial pneumonias (IIPs) are grouped into three categories; major, rare, and unclassifiable. Idiopathic pulmonary fibrosis (IPF) is one of the major IIPs and has been recognised as a distinct clinical entity since 2001. This has led to significant advances in our understanding and treatment of the disease and to the identification of new therapeutic targets. While multidisciplinary team assessment yields a definite diagnosis in many cases of interstitial lung disease (ILD), 15-25% of patients remain unclassifiable. This can be due to inadequate clinical, pathological, or radiological data (e.g., where a biopsy is not performed) or because results of investigations show major discrepancies, overlapping features, or mixed patterns. Patients with unclassifiable disease tend to be of similar age to those with IPF and older than those with connective tissue disorders. Survival of patients with unclassifiable disease is intermediate between IPF and non-IPF ILD. There is no single recommended treatment for patients with unclassifiable disease. However, the ILD-GAP index has recently been validated in this group and can risk-stratify patients based on four easily measurable variables. "Disease behaviour classification" (DBC) is an alternative, pragmatic approach to managing patients with unclassifiable disease. The ILD-GAP index has been shown to provide strong prognostic information in these hard-to-treat patients. In the future, new diagnostic tools such as protein biomarkers may become available to help guide therapeutic decisions.

Changes in the current classification of IIP: A critical review.

Idiopathic interstitial pneumonias (IIP) are a heterogeneous group characterized by unknown aetiology. Establishment of a correct diagnosis of a distinct IIP requires a multidisciplinary approach integrating clinical presentation, physiological data, radiological appearance and histological findings. The 2013 update of the American Thoracic Society/European Respiratory Society classification summarises progress in the field of IIP and outlines potential areas for future research. The main entities defined by the 2002 statement on IIP are preserved, but major IIP are now distinguished from rare IIP and the new category of unclassifiable IIP is introduced. In addition, the existence of idiopathic non-specific interstitial pneumonia as a separate chronic fibrosing IIP and idiopathic pleuroparenchymal fibroelastosis as a specific rare entity are acknowledged. Moreover, the major IIP are categorized according to the features chronic fibrosing, smoking-related and acute/subacute clinical course. Furthermore, a clinical classification of IIP according to disease behaviour with suggestions for treatment goals and monitoring strategies is provided. The goal of this review is to discuss the areas of uncertainty in the updated multidisciplinary classification of IIP and point out potential consequences for clinical management.

Rare idiopathic intestinal pneumonias (IIPs) and histologic patterns in new ATS/ERS multidisciplinary classification of the IIPs.

The new American Thoracic Society/European Respiratory Society (ATS/ERS) update to the multidisciplinary classification of idiopathic interstitial pneumonias (IIPs) defines both rare IIPs and rare histologic patterns of IIPs. Although these diseases are rare, each has some distinguishing imaging and pathologic characteristics. Common findings for IIPs in computed tomography (CT) include cysts in lymphoid interstitial pneumonia (LIP), upper lobe subpleural consolidation in pleuropulmonary fibroelastosis (PPFE), symmetrical consolidation in acute fibrinous organizing pneumonia (AFOP), and peribronchovascular consolidation or centrilobular nodules in bronchiolocentric pattern of interstitial pneumonia.

Idiopathic interstitial pneumonias: a radiology-pathology correlation based on the revised 2013 American Thoracic Society-European Respiratory Society classification system.

The idiopathic interstitial pneumonias (IIPs) are a group of diffuse lung diseases that share many similar radiologic and pathologic features. According to the revised 2013 American Thoracic Society-European Respiratory Society classification system, these entities are now divided into major IIPs (idiopathic pulmonary fibrosis, idiopathic nonspecific interstitial pneumonia, respiratory bronchiolitis-associated interstitial lung disease, desquamative interstitial pneumonia, cryptogenic organizing pneumonia, and acute interstitial pneumonia), rare IIPs (idiopathic lymphoid interstitial pneumonia, idiopathic pleuroparenchymal fibroelastosis), and unclassifiable idiopathic interstitial pneumonias. Some of the encountered radiologic and histologic patterns can also be seen in the setting of other disorders, which makes them a diagnostic challenge. As such, the accurate classification of IIPs remains complex and is best approached through a collaboration among clinicians, radiologists, and pathologists, as the treatment and prognosis of these conditions vary greatly.

[Idiopathic interstitial pneumonias]. / Pneumopathies interstitielles diffuses idiopathiques.

Idiopathic interstitial pneumonias represent approximately 30% of all interstitial lung diseases. The new classification of idiopathic interstitial pneumonias published in 2013 distinguishes 6 major entities, including chronic fibrosing forms (idiopathic pulmonary fibrosis and nonspecific interstitial pneumonia), acute/subacute forms (cryptogenic organizing pneumonia and acute interstitial pneumonia) and smoking-related disorders (respiratory bronchiolitis interstitial lung disease and desquamative interstitial pneumonia). Pleuroparenchymal fibroelastosis is individualized as a new rare clinco-pathologic entity. For cases not fitting any specific clinic- pathological category, a pragmatic classification based on disease behavior is proposed.

The idiopathic interstitial pneumonias: an update and review.

Idiopathic interstitial pneumonias (IIPs) are a group of disorders with distinct histologic and radiologic appearances and no identifiable cause. The IIPs comprise 8 currently recognized entities. Each of these entities demonstrates a prototypical imaging and histologic pattern, although in practice the imaging patterns may overlap, and some interstitial pneumonias are not classifiable. To be considered an IIP, the disease must be idiopathic; however, each pattern may be secondary to a recognizable cause, most notably collagen vascular disease, hypersensitivity pneumonitis, or drug reactions. The diagnosis of IIP requires the correlation of clinical, imaging, and pathologic features.