Incidental nonneoplastic parenchymal findings in patients undergoing lung resection for mass lesions

Outcome of immune checkpoint inhibitor treatment in non-small cell lung cancer patients with interstitial lung abnormalities: clinical utility of subcategorizing interstitial lung abnormalities

Interstitial lung abnormalities (ILAs) are immune checkpoint inhibitor (ICI)-related pneumonitis (ICI-P) risk factors. However, the relationship between imaging patterns and immunotherapy outcomes, and treatment strategies remain unclear in patients with non-small cell lung cancer (NSCLC) and ILAs. We retrospectively evaluated patients with ILAs-complicated NSCLC who received ICI therapy. ILAs were subcategorized as non-subpleural, subpleural non-fibrotic, and subpleural fibrotic (SF) based on the 2020 position paper by the Fleischner Society. We investigated ICI-P incidence, ICI-P risk factors, lung cancer prognosis, and ILAs radiological progression. Of the 481 ICI-treated patients, 79 (16.4%) had ILAs (45 non-SF and 34 SF). The ICI-P cumulative incidence (hazard ratio, 4.57; 95% confidence interval [CI], 1.90-10.98; p = 0.001) and any grade and grade ≥ 3 ICI-P incidences were higher in patients with SF-ILAs than in those with non-SF-ILAs (all grades: 7/45 [15.6%)] vs. 18/34 [52.9%]; p < 0.001; grade ≥ 3: 1/45 [2.2%] vs. 10/34 [29.4%]; p = 0.001). According to multivariate analysis, SF-ILAs independently predicted ICI-P (odds ratio, 5.35; 95% CI 1.62-17.61; p = 0.006). Patients with SF-ILAs had shorter progression-free and overall survival and higher ICI-P-related respiratory failure death rates than those with non-SF-ILAs. Approximately 2.5 times more patients with SF-ILAs showed progression by the 2-year follow-up than those with non-SF-ILAs. SF-ILAs is an independent strong predictor of ICI-P development in patients with NSCLC, may increase ICI-P severity, worsen prognosis, and accelerate ILAs progression. ILAs subcategorization is an important treatment strategy for patients with lung cancer treated with ICIs.

Reporting of Incidental Thrombotic Arteriopathy in Lung Resection Specimens: Examination of Clinical Impact

Pulmonary thrombotic arteriopathy (PTA) can be an incidental finding in lung resections performed for various indications. Historic studies largely examined PTA in autopsies. Thus, the prevalence in surgical samples, particularly in the modern era of lung cancer screening, is poorly defined. Detection of PTA in surgical samples may provide an opportunity for therapeutic intervention, but the impact of this finding on clinical management is unknown. We retrospectively examined consecutive lung surgical resections containing a report of incidental PTA between 2019 and 2022 in our institution. A retrospective chart review was performed to determine the history of systemic thromboembolism and clinical and radiographic follow-up. All slides were reviewed to morphologically characterize the vascular changes. Among 2930 pulmonary resections, 66 (2.3%) reportedly contained PTA. Twenty-four (36.4%) patients had a clinically recognized thromboembolic event either before or after surgical resection. Patients with clinically recognized thromboembolic disease were significantly more likely to have both acute and organized thrombi affecting large arteries. The presence of infarct, chronic hypertensive vasculopathy, or number of vessels with thrombi were not significantly associated with a clinically detected event. Reporting of incidental PTA led to clinical intervention in six patients and confirmed systemic thromboembolic disease in 2. Moreover, 2 patients with no further workup based on the incidental pathology findings subsequently developed pulmonary embolism. PTA is incidentally detected in 2.3% of surgical lung resections, and in two-thirds of cases, there is no clinical suspicion of thromboembolic disease. Pathologic reporting of PTA rarely led to clinical intervention, suggesting a need for improved communication of incidental pathology findings.

Interstitial Lung Abnormalities

Interstitial lung abnormalities (ILA) is a radiographic term, which has recently undergone clarification of definition with creation of 3 subtypes. ILA is defined as incidental identification of computed tomography abnormalities in a patient who is not suspected of having an interstitial lung disease (ILD). A subset of ILA may progress to clinically significant ILD and is associated with morbidities not related to progression such as an increased incidence of sepsis-related acute respiratory distress syndrome (ARDS). ILA has been associated with an increased incidence of treatment-related complications in patients with lung cancer. Information on corresponding histology is limited; knowledge gaps exist concerning optimal patient management.

Interstitial Lung Abnormalities: Current Understanding

Interstitial lung abnormalities (ILAs) are incidental findings on computed tomography scans, characterized by nondependent abnormalities affecting more than 5% of any lung zone. They are associated with factors such as age, smoking, genetic variants, worsened clinical outcomes, and increased mortality. Risk stratification based on clinical and radiological features of ILAs is crucial in clinical practice, particularly for identifying cases at high risk of progression to pulmonary fibrosis. Traction bronchiectasis/bronchiolectasis index has emerged as a promising imaging biomarker for prognostic risk stratification in ILAs. These findings suggest a spectrum of fibrosing interstitial lung diseases, encompassing from ILAs to pulmonary fibrosis.

Prevalence and prognostic meaning of interstitial lung abnormalities in remote CT scans of patients with interstitial lung disease treated with antifibrotic therapy

OBJECTIVES

To describe the prevalence and characteristics of interstitial lung abnormalities (ILA) in CT scans performed prior to the initiation of antifibrotics in a series of patients with interstitial lung disease (ILD), and to identify characteristics apparent on early CT scans that could help to predict outcomes.

METHODS

We conducted a retrospective observational study. The original cohort consisted of 101 patients diagnosed with ILD and treated with antifibrotics in a tertiary hospital. Patients were included if they had a thoracic CT scan performed at least one year before initiation of therapy. They were classified radiologically in three groups: without ILA, with radiological ILA and extensive abnormalities. ILA were classified as subpleural fibrotic, subpleural non-fibrotic and non-subpleural. The initial scan and the latest CT scan performed before treatment were read for assessing progression. The relationship between CT findings of fibrosis and the radiological progression rate and mortality were analyzed.

RESULTS

We included 50 patients. Only 1 (2%) had a normal CT scan, 25 (50%) had extensive alterations and 24 (48%) had radiological criteria for ILA, a median of 98.2 months before initiation of antifibrotics, of them 18 (75%) had a subpleural fibrotic pattern. Significant bronchiectasis and obvious honeycombing in the lower zones were associated with shorter survival (p = 0.04). Obvious honeycombing in the lower zones was also significantly (p < 0.05) associated with a faster progression rate.

CONCLUSIONS

Fibrotic ILAs are frequent in remote scans of patients with clinically relevant ILD, long before they require antifibrotics. Findings of traction bronchiectasis and honeycombing in the earliest scans, even in asymptomatic patients, are related to mortality and progression later on.

Frequency of subclinical interstitial lung disease in COVID-19 autopsy cases: potential risk factors of severe pneumonia

Risk factors of severe coronavirus disease 2019 (COVID-19) have been previously reported; however, histological risk factors have not been defined thus far. The aim of this study was to clarify subclinical hidden interstitial lung disease (ILD) as a risk factor of severe pneumonia associated with COVID-19. We carefully examined autopsied lungs and chest computed tomography scanning (CT) images from patients with COVID-19 for interstitial lesions and then analyzed their relationship with disease severity. Among the autopsy series, subclinical ILD was found in 13/27 cases (48%) in the COVID-19 group, and in contrast, 8/65 (12%) in the control autopsy group (p = 0.0006; Fisher's exact test). We reviewed CT images from the COVID-19 autopsy cases and verified that subclinical ILD was histologically detectable in the CT images. Then, we retrospectively examined CT images from another series of COVID-19 cases in the Yokohama, Japan area between February-August 2020 for interstitial lesions and analyzed the relationship to the severity of COVID-19 pneumonia. Interstitial lesion was more frequently found in the group with the moderate II/severe disease than in the moderate I/mild disease (severity was evaluated according to the COVID-19 severity classification system of the Ministry of Health, Labor, and Welfare [Japan]) (moderate II/severe, 11/15, 73.3% versus moderate I/mild, 108/245, 44.1%; Fisher exact test, p = 0.0333). In conclusion, it was suggested that subclinical ILD could be an important risk factor for severe COVID-19 pneumonia. A benefit of these findings could be the development of a risk assessment system using high resolution CT images for fatal COVID-19 pneumonia.

Survival impact of fibrotic interstitial lung abnormalities in resected stage IA non-small cell lung cancer

OBJECTIVES

To assess the association between fibrotic interstitial lung abnormalities (ILAs) and long-term survival in patients with resected Stage IA non-small cell lung cancer (NSCLC).

METHODS

Data of patients who underwent curative resection of pathological Stage IA NSCLC between 2010 and 2015 were retrospectively analysed. ILAs were evaluated using pre-operative high-resolution CT scans. The association between ILAs and cause-specific mortality was assessed via Kaplan-Meier analysis and the log-rank test. Cox proportional hazards regression was performed to determine the risk factors for cause-specific death.

RESULTS

Overall, 228 patients were identified (63.27 ± 8.54 years, 133 men [58.3%]). ILAs were detected in 24 patients (10.53%). Fibrotic ILAs were observed in 16 patients (7.02%), and there was a significantly higher cause-specific mortality rate among patients with fibrotic ILAs compared with patients with no ILAs (p < 0.001). Patients with fibrotic ILAs had a significantly higher cause-specific mortality rate than patients without ILAs at 5 post-operative years (survival rate: 61.88% vs 93.03%, p < 0.001). The presence of afibrotic ILA was an independent risk factor for cause-specific death (adjusted hazard ratio = 3.22; 95% confidence interval: 1.10, 9.44; p = 0.033).

CONCLUSION

The presence of afibrotic ILA was a risk factor for cause-specific death in patients with resected Stage IA NSCLC. Radiologists and clinicians should be familiar with the relatively new concept of ILAs and understand the close association between ILA status and long-term survival in resected Stage IA NSCLC. Patients presenting fibrotic ILAs should receive appropriate surveillance and management to optimise prognosis.

ADVANCES IN KNOWLEDGE

Fibrotic ILAs are important findings implicated inthe long-term survival of patients with resected Stage IA NSCLC. Specific management is required for this group.

Are Interstitial Lung Abnormalities a Prognostic Factor of Worse Outcome in COVID-19 Pneumonia?

PURPOSE

To assess the association between interstitial lung abnormalities (ILAs) and worse outcome in patients affected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease (COVID-19)-related pneumonia.

MATERIALS AND METHODS

The study included patients older than 18 years, who were admitted at the emergency department between February 29 and April 30, 2020 with findings of COVID-19 pneumonia at chest computed tomography (CT), with positive reverse-transcription polymerase chain reaction nasal-pharyngeal swab for SARS-CoV-2, and with the availability of prepandemic chest CT. Prepandemic CTs were reviewed for the presence of ILAs, categorized as fibrotic in cases with associated architectural distortion, bronchiectasis, or honeycombing. Worse outcome was defined as intensive care unit (ICU) admission or death. Cox proportional hazards regression analysis was used to test the association between ICU admission/death and preexisting ILAs.

RESULTS

The study included 147 patients (median age 73 y old; 95% CIs: 71-76-y old; 29% females). On prepandemic CTs, ILA were identified in 33/147 (22%) of the patients, 63% of which were fibrotic ILAs. Fibrotic ILAs were associated with higher risk of ICU admission or death in patients with COVID-19 pneumonia (hazard ratios: 2.73, 95% CIs: 1.50-4.97, P =0.001).

CONCLUSIONS

In patients affected by COVID-19 pneumonia, preexisting fibrotic ILAs were an independent predictor of worse prognosis, with a 2.7 times increased risk of ICU admission or death. Chest CT scans obtained before the diagnosis of COVID-19 pneumonia should be carefully reviewed for the presence and characterization of ILAs.

Radiologic and Histologic Correlates of Early Interstitial Lung Changes in Explanted Lungs

Background Interstitial lung abnormalities (ILAs) reflect imaging features on lung CT scans that are compatible with (early) interstitial lung disease. Despite accumulating evidence regarding the incidence, risk factors, and prognosis of ILAs, the histopathologic correlates of ILAs remain elusive. Purpose To determine the correlation between radiologic and histopathologic findings in CT-defined ILAs in human lung explants. Materials and Methods Explanted lungs or lobes from participants with radiologically documented ILAs were prospectively collected from 2010 to 2021. These specimens were air-inflated, frozen, and scanned with CT and micro-CT (spatial resolution of 0.7 mm and 90 μm, respectively). Subsequently, the lungs were cut and sampled with core biopsies. At least five samples per lung underwent micro-CT and subsequent histopathologic assessment with semiquantitative remodeling scorings. Based on area-specific radiologic scoring, the association between radiologic and histopathologic findings was assessed. Results Eight lung explants from six donors (median age at explantation, 71 years [range, 60-83 years]; four men) were included (unused donor lungs, n = 4; pre-emptive lobectomy for oncologic indications, n = 2). Ex vivo CT demonstrated ground-glass opacification, reticulation, and bronchiectasis. Micro-CT and histopathologic examination demonstrated that lung abnormalities were frequently paraseptal and associated with fibrosis and lymphocytic inflammation. The histopathologic results showed varying degrees of fibrosis in areas that appeared normal on CT scans. Regions of reticulation on CT scans generally had greater fibrosis at histopathologic analysis. Vasculopathy and bronchiectasis were also often present at histopathologic examination of lungs with ILAs. Fully developed fibroblastic foci were rarely observed. Conclusion This study demonstrated direct histologic correlates of CT-defined interstitial lung abnormalities. © RSNA, 2022 Supplemental material is available for this article. See also the editorial by Jeudy in this issue.

Interstitial Lung Abnormalities at CT: Subtypes, Clinical Significance, and Associations with Lung Cancer

Interstitial lung abnormality (ILA) is defined as an interstitial change detected incidentally on CT images. It is seen in 4%-9% of smokers and 2%-7% of nonsmokers. ILA has a tendency to progress with time and is associated with respiratory symptoms, decreased exercise capability, reduced pulmonary function, and increased mortality. ILAs can be classified into three subcategories: nonsubpleural, subpleural nonfibrotic, and subpleural fibrotic. In cases of ILA, clinically significant interstitial lung disease should be identified and requires clinically driven management by a pulmonologist. Risk factors for the progression of ILA include clinical elements (ie, inhalation exposures, medication use, radiation therapy, thoracic surgery, physiologic findings, and gas exchange findings) and radiologic elements (ie, basal and peripheral predominance and fibrotic findings). It is recommended that individuals with one or more clinical or radiologic risk factors for progression of ILA be actively monitored with pulmonary function testing and CT. To avoid overcalling ILA at CT, radiologists must recognize the imaging pitfalls, including centrilobular nodularity, dependent abnormality, suboptimal inspiration, osteophyte-related lesions, apical cap and pleuroparenchymal fibroelastosis-like lesions, aspiration, and infection. There is a close association between ILA and lung cancer, and many studies have reported an increased incidence of lung cancer, worse prognoses, and/or increased pulmonary complications in relation to cancer treatment in patients with ILA. ILA is considered to be an important comorbidity in patients with lung cancer. Accordingly, all radiologists involved with body CT must have sound knowledge of ILAs owing to the high prevalence and potential clinical significance of these anomalies. An overview of ILAs, including a literature review of the associations between ILAs and lung cancer, is presented. ©RSNA, 2022.

Incidental discovery of interstitial lung disease: diagnostic approach, surveillance and perspectives

The incidental discovery of pre-clinical interstitial lung disease (ILD) has led to the designation of interstitial lung abnormalities (ILA), a radiological entity defined as the incidental finding of computed tomography (CT) abnormalities affecting more than 5% of any lung zone. Two recent documents have redefined the borders of this entity and made the recommendation to monitor patients with ILA at risk of progression. In this narrative review, we will focus on some of the limits of the current approach, underlying the potential for progression to full-blown ILD of some patients with ILA and the numerous links between subpleural fibrotic ILA and idiopathic pulmonary fibrosis (IPF). Considering the large prevalence of ILA in the general population (7%), restricting monitoring only to cases considered at risk of progression appears a reasonable approach. However, this suggestion should not prevent pulmonary physicians from pursuing an early diagnosis of ILD and timely treatment where appropriate. In cases of suspected ILD, whether found incidentally or not, the pulmonary physician is still required to make a correct ILD diagnosis according to current guidelines, and eventually treat the patient accordingly.

In patients with interstitial lung abnormalities (ILA), monitoring of those at risk of progression is currently recommended, and pulmonary physicians should pursue an early diagnosis when ILA become clinically significant to facilitate timely treatment https://bit.ly/3HKOQc8

Cigarette Smoke Particle-Induced Lung Injury and Iron Homeostasis

It is proposed that the mechanistic basis for non-neoplastic lung injury with cigarette smoking is a disruption of iron homeostasis in cells after exposure to cigarette smoke particle (CSP). Following the complexation and sequestration of intracellular iron by CSP, the host response (eg, inflammation, mucus production, and fibrosis) attempts to reverse a functional metal deficiency. Clinical manifestations of this response can present as respiratory bronchiolitis, desquamative interstitial pneumonitis, pulmonary Langerhans’ cell histiocytosis, asthma, pulmonary hypertension, chronic bronchitis, and pulmonary fibrosis. If the response is unsuccessful, the functional deficiency of iron progresses to irreversible cell death evident in emphysema and bronchiectasis. The subsequent clinical and pathological presentation is a continuum of lung injuries, which overlap and coexist with one another. Designating these non-neoplastic lung injuries after smoking as distinct disease processes fails to recognize shared relationships to each other and ultimately to CSP, as well as the common mechanistic pathway (ie, disruption of iron homeostasis).

Interstitial lung abnormalities - current knowledge and future directions

Efforts to grasp the significance of radiologic changes similar to interstitial lung disease (ILD) in undiagnosed individuals have intensified in the recent decade. The term interstitial lung abnormalities (ILA) is an emerging definition of such changes, defined by visual examination of computed tomography scans. Substantial insights have been made in the origins and clinical consequences of these changes, as well as automated measures of early lung fibrosis, which will likely lead to increased recognition of early fibrotic lung changes among clinicians and researchers alike.

Interstitial lung abnormalities have an estimated prevalence of 7–10% in elderly populations. They correlate with many ILD risk factors, both epidemiologic and genetic. Additionally, histopathological similarities with IPF exist in those with ILA. While no established blood biomarker of ILA exists, several have been suggested. Distinct imaging patterns indicating advanced fibrosis correlate with worse clinical outcomes. ILA are also linked with adverse clinical outcomes such as increased mortality and risk of lung cancer.

Progression of ILA has been noted in a significant portion of those with ILA and is associated with many of the same features as ILD, including advanced fibrosis. Those with ILA progression are at risk of accelerated FVC decline and increased mortality. Radiologic changes resembling ILD have also been attained by automated measures. Such measures associate with some, but not all the same factors as ILA.

ILA and similar radiologic changes are in many ways analogous to ILD and likely represent a precursor of ILD in some cases. While warranting an evaluation for ILD, they are associated with poor clinical outcomes beyond possible ILD development and thus are by themselves a significant finding. Among the present objectives of this field are the stratification of patients with regards to progression and the discovery of biomarkers with predictive value for clinical outcomes.

Clinical Relevance and Management of "Pre-Interstitial Lung Disease"

Cellular level changes that lead to interstitial lung disease (ILD) may take years to become clinically apparent and have been termed preclinical ILD. Incidentally identified interstitial lung abnormalities (ILA) are increasingly being recognized on chest computed tomographic scans done as part of lung cancer screening and for other purposes. Many individuals found to have ILA will progress to clinically significant ILD. ILA are independently associated with greater risk of death, lung function decline, and incident lung cancer. Current management recommendations focus on identifying individuals with ILA at high risk of progression, through a combination of clinical and radiological features.

Interstitial lung abnormality (ILA) and nonspecific interstitial pneumonia (NSIP)

This review article aims to address mysteries existing between Interstitial Lung Abnormality (ILA) and Nonspecific Interstitial Pneumonia (NSIP). The concept and definition of ILA are based upon CT scans from multiple large-scale cohort studies, whereas the concept and definition of NSIP originally derived from pathology with evolution to multi-disciplinary diagnosis. NSIP is the diagnosis as Interstitial Lung Disease (ILD) with clinical significance, whereas only a part of subjects with ILA have clinically significant ILD. Eventually, both ILA and NSIP must be understood in the context of chronic fibrosing ILD and progressive ILD, which remains to be further investigated.

Interstitial lung abnormalities detected incidentally on CT: a Position Paper from the Fleischner Society

The term interstitial lung abnormalities refers to specific CT findings that are potentially compatible with interstitial lung disease in patients without clinical suspicion of the disease. Interstitial lung abnormalities are increasingly recognised as a common feature on CT of the lung in older individuals, occurring in 4-9% of smokers and 2-7% of non-smokers. Identification of interstitial lung abnormalities will increase with implementation of lung cancer screening, along with increased use of CT for other diagnostic purposes. These abnormalities are associated with radiological progression, increased mortality, and the risk of complications from medical interventions, such as chemotherapy and surgery. Management requires distinguishing interstitial lung abnormalities that represent clinically significant interstitial lung disease from those that are subclinical. In particular, it is important to identify the subpleural fibrotic subtype, which is more likely to progress and to be associated with mortality. This multidisciplinary Position Paper by the Fleischner Society addresses important issues regarding interstitial lung abnormalities, including standardisation of the definition and terminology; predisposing risk factors; clinical outcomes; options for initial evaluation, monitoring, and management; the role of quantitative evaluation; and future research needs.

A case report of pulmonary amyloidosis recognized by detection of AA amyloid exclusively in alveolar macrophages

Amyloidosis is a rare condition in which tissue deposits of inert fibrillar protein result in organ damage and dysfunction. There are several types of amyloid fibrils. Some of the most common forms are AL (amyloid light chain) protein and AA (amyloid-associated) type of amyloid fibril protein. Pulmonary amyloidosis is relatively common but is usually asymptomatic. Thus, the diagnosis may be easily overlooked. A 78-year-old male with a history of multiple myeloma followed by systemic amyloidosis presented with abnormal chest CT showing diffuse interlobular thickening in the whole lung field with bilateral pleural effusion. Bronchoalveolar lavage and transbronchial biopsy were performed. Due to the patient's poor condition and hemorrhage, only one fragment was available from forceps biopsy. Histologically, there was no amyloid deposition in the lung parenchyma; however, some histiocytes showed eosinophilic granular contents which prompted us to perform additional staining. The cytoplasmic material turned to be positive with direct fast scarlet (DFS) staining and AA amyloid immunostaining. Similar macrophages with AA amyloid were also found in the bronchoalveolar fluid. We experienced a case with AA amyloidosis affecting the lung diagnosed by the presence of intracytoplasmic amyloid in alveolar macrophages. The microscopic changes were so subtle that they may be overlooked. Recognition of amyloid deposition in alveolar macrophages may be an important clue to diagnose pulmonary amyloidosis. Such finding is of particular significance in the small-sized specimens, such as biopsies and cytologic smears.