Clinical, radiological, and pathological evaluation of "NSIP with OP overlap" pattern compared with NSIP in patients with idiopathic interstitial pneumonias

Imaging of Pulmonary Manifestations of Connective Tissue Disease

The majority of connective tissue diseases (CTDs) are multisystem disorders that are often heterogeneous in their presentation and do not have a single laboratory, histologic, or radiologic feature that is defined as the gold standard to support a specific diagnosis. Given this challenging situation, the diagnosis of CTD is a process that requires the synthesis of multidisciplinary data which may include patient clinical symptoms, serologic evaluation, laboratory testing, and imaging. Pulmonary manifestations of connective tissue disease include interstitial lung disease as well as multicompartmental manifestations. These CT imaging patterns and features of specific diseases will be discussed in this article.

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.

Radiological and histopathological features and treatment response by subtypes of interstitial pneumonia with autoimmune features: A prospective, multicentre cohort study

BACKGROUND

Patients with idiopathic interstitial pneumonia (IIP) have a favourable prognosis when they have interstitial pneumonia with autoimmune features (IPAF). However, precise IPAF-related findings from high-resolution computed tomography (HRCT) and lung histopathological specimens and the treatment response have not been fully determined. Therefore, this study was conducted to evaluate the relationship between findings on HRCT or lung histopathological specimens and the progression of interstitial pneumonia in patients with IPAF.

METHODS

This multicentre cohort study prospectively enrolled consecutive patients with IIP. At the diagnosis of IIP, we systematically evaluated 74 features suggestive of connective tissue diseases and followed them up. HRCT, lung specimens, serum antibodies, and the clinical course were also evaluated.

RESULTS

Among 222 patients with IIP, 26 (11.7%) fulfilled the IPAF criteria. During a median observation period of 36 months, patients with IPAF showed better survival than those without IPAF (p = 0.034). While histopathological findings were not related to IPAF, nonspecific interstitial pneumonia (NSIP) with organizing pneumonia (OP) overlap was the most prevalent HRCT pattern (p < 0.001) and the consolidation opacity was the most common radiological finding in IPAF (p = 0.017). Furthermore, in patients with IPAF, the diagnosis of COP or NSIP with OP overlap was associated with a higher increase in %FVC in 1 year than in those with idiopathic pulmonary fibrosis, NSIP, or unclassifiable IIP (p = 0.002).

CONCLUSIONS

This study shows the presence of consolidation opacity on HRCT and the diagnosis of COP or NSIP with OP overlap are associated with IPAF and its favourable treatment response in patients with IPAF.

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.

Nonspecific interstitial pneumonia pattern is a frequent finding in patients with post-acute COVID-19 syndrome treated with bilateral orthotopic lung transplantation: current best evidence

Patients with post-acute COVID-19 (PA-COVID) syndrome or long COVID-19 syndrome develop persistent symptoms and complications that last beyond 4 weeks of the initial infection. There is limited information regarding the pulmonary pathology in PA-COVID patients who require bilateral orthotopic lung transplantation (BOLT). Our experience with 40 lung explants from 20 PA-COVID patients who underwent BOLT is described. Clinicopathologic findings are correlated with best evidence from literature. The lung parenchyma showed bronchiectasis (n = 20) and severe interstitial fibrosis with areas resembling the nonspecific interstitial pneumonia (NSIP) pattern of fibrosis (n = 20), interstitial fibrosis not otherwise specified (n = 20), and fibrotic cysts (n = 9). None of the explants exhibited a usual interstitial pneumonia pattern of fibrosis. Other parenchymal changes included multinucleated giant cells (n = 17), hemosiderosis (n = 16), peribronchiolar metaplasia (n = 19), obliterative bronchiolitis (n = 6), and microscopic honeycombing (n = 5). Vascular abnormalities included thrombosis of a lobar artery (n = 1) and microscopic thrombi in small vessels (n = 7). Systematic literature review identified 7 articles reporting the presence in 12 patients of interstitial fibrosis showing the NSIP pattern (n = 3), organizing pneumonia/diffuse alveolar damage (n = 4) and not otherwise specified (n = 3) patterns. All but one of these studies also reported the presence of multinucleated giant cells and none of the studies reported the presence of severe vascular abnormalities. PA-COVID patients undergoing BOLT show a pattern of fibrosis that resembles a mixed cellular-fibrotic NSIP pattern and generally lack severe vascular complications. As the NSIP pattern of fibrosis is often associated with autoimmune diseases, additional studies are needed to understand the mechanism of disease and learn whether this information can be used for therapeutic purposes.

Clinical features of relapsed connective tissue disease-associated organizing pneumonia

BACKGROUND

Organizing pneumonia (OP) is recognized as a nonspecific lung injury response characterized histopathologically by the presence of intra-alveolar buds of granulation tissue. Most OP patients show excellent responses to corticosteroids, but relapse is frequently seen when corticosteroids are tapered or discontinued. Although several factors associated with relapse have been reported in cryptogenic OP (COP), the clinical features and risk factors associated with relapse in connective tissue disease-associated OP (CTD-OP) have yet to be fully understood.

METHODS

We retrospectively reviewed data on 47 CTD-OP patients. We investigated the frequency of relapse and compared the clinical data between CTD-OP with and without relapse to clarify the risk factors for relapse.

RESULTS

Eleven (23.4%) CTD-OP patients had relapses of OP during the study. In the multivariate analysis, no CTD treatment at OP diagnosis [O.R. 11.920, p = 0.012] and partial remission after steroid treatment [O.R. 35.944, p = 0.045] were independent risk factors for relapse. Among rheumatoid arthritis-associated OP (RA-OP) patients, partial remission after steroid treatment [O.R. 16.151, p = 0.047] and age at OP diagnosis [O.R. 0.899, p = 0.045] were independent risk factors for relapse. Most of the relapsed OP patients who were on no medication at OP diagnosis later developed CTD.

CONCLUSION

CTD-OP patients with residual disease on HRCT after treatment and who had OP diagnosis preceding CTD diagnosis were more likely to have an OP relapse. During the clinical course of relapsed OP patients, it is necessary to pay attention to the onset of CTD.

High-Resolution Computed Tomography of Fibrotic Interstitial Lung Disease

While radiography is the first-line imaging technique for evaluation of pulmonary disease, high-resolution computed tomography (HRCT) provides detailed assessment of the lung parenchyma and interstitium, allowing normal anatomy to be differentiated from superimposed abnormal findings. The fibrotic interstitial lung diseases have HRCT features that include reticulation, traction bronchiectasis and bronchiolectasis, honeycombing, architectural distortion, and volume loss. The characterization and distribution of these features result in distinctive CT patterns. The CT pattern and its progression over time can be combined with clinical, serologic, and pathologic data during multidisciplinary discussion to establish a clinical diagnosis. Serial examinations identify progression, treatment response, complications, and can assist in determining prognosis. This article will describe the technique used to perform HRCT, the normal and abnormal appearance of the lung on HRCT, and the CT patterns identified in common fibrotic lung diseases.

Algorithmic Approach to the Diagnosis of Organizing Pneumonia: A Correlation of Clinical, Radiologic, and Pathologic Features

Organizing pneumonia (OP), characterized histopathologically by patchy filling of alveoli and bronchioles by loose plugs of connective tissue, may be seen in a variety of conditions. These include but are not limited to after an infection, drug reactions, radiation therapy, and collagen vascular diseases. When a specific cause is responsible for this entity, it is referred to as "secondary OP." When an extensive search fails to reveal a cause, it is referred to as "cryptogenic OP" (previously called "bronchiolitis obliterans with OP"), which is a clinical, radiologic, and pathologic entity classified as an interstitial lung disease. The clinical presentation of OP often mimics that of other disorders, such as infection and cancer, which can result in a delay in diagnosis and inappropriate management of the underlying disease. The radiographic presentation of OP is polymorphous but often has subpleural consolidations with air bronchograms or solitary or multiple nodules, which can wax and wane. Diagnosis of OP sometimes requires histopathologic confirmation and exclusion of other possible causes. Treatment usually requires a prolonged steroid course, and disease relapse is common. The aim of this article is to summarize the clinical, radiographic, and histologic presentations of this disease and to provide a practical diagnostic algorithmic approach incorporating clinical history and characteristic imaging patterns.

Clinical, radiological, and pathological findings in patients with persistent lung disease following SARS-CoV-2 infection

Some patients experience pulmonary sequelae after SARS-CoV-2 infection, ranging from self-limited abnormalities to major lung diseases. Morphological analysis of lung tissue may help our understanding of pathogenic mechanisms and help to provide consistent personalised management. The aim of this study was to ascertain morphological and immunomolecular features of lung tissue. Transbronchial lung cryobiopsy was carried out in patients with persistent symptoms and computed tomography suggestive of residual lung disease after recovery from SARS-CoV-2 infection. 164 patients were referred for suspected pulmonary sequelae after COVID-19; 10 patients with >5% parenchymal lung disease underwent lung biopsy. The histological pattern of lung disease was not homogeneous and three different case clusters could be identified, which was mirrored by their clinical and radiological features. Cluster 1 (“chronic fibrosing”) was characterised by post-infection progression of pre-existing interstitial pneumonias. Cluster 2 (“acute/subacute injury”) was characterised by different types and grades of lung injury, ranging from organising pneumonia and fibrosing nonspecific interstitial pneumonia to diffuse alveolar damage. Cluster 3 (“vascular changes”) was characterised by diffuse vascular increase, dilatation and distortion (capillaries and venules) within otherwise normal parenchyma. Clusters 2 and 3 had immunophenotypical changes similar to those observed in early/mild COVID-19 pneumonias (abnormal expression of STAT3 in hyperplastic pneumocytes and PD-L1, IDO and STAT3 in endothelial cells). This is the first study correlating histological/immunohistochemical patterns with clinical and radiological pictures of patients with post-COVID lung disease. Different phenotypes with potentially different underlying pathogenic mechanisms have been identified.

Post-COVID lung disease is not a single entity, but includes different subtypes, each of them potentially requiring separate and different managementhttps://bit.ly/3BJDeUF

[Cryptogenic organizing pneumonia versus secondary organizing pneumonia]

Die organisierende Pneumonie (OP) beschreibt ein histologisches Muster des akuten bzw. subakuten Lungenschadens. Klinisch fallen die Patienten mit Husten, Fieber und Dyspnoe auf. Es wird zwischen der idiopathischen bzw. kryptogen organisierenden (COP) und der sekundären organisierenden Pneumonie (OP) unterschieden. Bei der COP kann weder klinisch/radiologisch noch histologisch eine Ursache bestimmt werden. Sie wird zu den interstitiellen idiopathischen Pneumonien (IIP) gezählt nach Kriterien der American Thoracic Society (ATS) und der European Respiratory Society (ERS). Bei der sekundären organisierenden Pneumonie liegt ein bekannter auslösender Mechanismus vor, wie z. B. infektiöse Erreger, bestimmte Medikamente oder auch Begleiterscheinungen anderer primär pulmonaler Erkrankungen und Erkrankungen anderer Organsysteme. Beiden Formen gemeinsam ist das histologische Bild der intraalveolären Mesenchymknospen. Diese sind Myofibroblastenproliferate, welche sich zopfartig entlang der Alveolarräume verzweigen. Sie werden in der Regel von einem bis mäßigen interstitiellen und alveolären, chronischen und makrophagenreichen Entzündungszellinfiltrat begleitet. Wichtigste Differenzialdiagnose ist die gewöhnliche interstitielle Pneumonie (UIP). Diese zeigt ebenfalls Fibroblastenproliferate, welche allerdings interstitiell liegen. Die korrekte Zuordnung einer IIP als COP mittels klinischer, radiologischer und histologischer Befunderhebung ist essenziell, da die COP im Gegensatz zur UIP sehr gut auf Kortikosteroide anspricht und somit gegenüber der UIP eine exzellente Prognose hat. Der Verlauf sekundärer organisierender Pneumonien hängt von der jeweiligen Grunderkrankung ab. Hier ist es wichtig, dass der Pathologe histologische Begleitcharakteristika einer OP korrekt identifiziert, um Hinweise auf eine mögliche Ursache geben zu können.