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.

Stepwise diagnostic algorithm for high-attenuation pulmonary abnormalities on CT.

High-attenuation pulmonary abnormalities are commonly seen on CT. These findings are increasingly encountered with the growing number of CT examinations and the wide availability of thin-slice images. The abnormalities include benign lesions, such as infectious granulomatous diseases and metabolic diseases, and malignant tumors, such as lung cancers and metastatic tumors. Due to the wide spectrum of diseases, the proper diagnosis of high-attenuation abnormalities can be challenging. The assessment of these abnormal findings requires scrutiny, and the treatment is imperative. Our proposed stepwise diagnostic algorithm consists of five steps. Step 1: Establish the presence or absence of metallic artifacts. Step 2: Identify associated nodular or mass-like soft tissue components. Step 3: Establish the presence of solitary or multiple lesions if identified in Step 2. Step 4: Ascertain the predominant distribution in the upper or lower lungs if not identified in Step 2. Step 5: Identify the morphological pattern, such as linear, consolidation, nodular, or micronodular if not identified in Step 4. These five steps to diagnosing high-attenuation abnormalities subdivide the lesions into nine categories. This stepwise radiologic diagnostic approach could help to narrow the differential diagnosis for various pulmonary high-attenuation abnormalities and to achieve a precise diagnosis.Critical relevance statement Our proposed stepwise diagnostic algorithm for high-attenuation pulmonary abnormalities may help to recognize a variety of those high-attenuation findings, to determine whether the associated diseases require further investigation, and to guide appropriate patient management. Key points • To provide a stepwise diagnostic approach to high-attenuation pulmonary abnormalities.• To familiarize radiologists with the varying cause of high-attenuation pulmonary abnormalities.• To recognize which high-attenuation abnormalities require scrutiny and prompt treatment.

Autoimmune Pulmonary Alveolar Proteinosis Complicated by Myelodysplastic Syndrome: A Case Report.

Pulmonary alveolar proteinosis (PAP) is characterized by an abnormal surfactant accumulation in peripheral air spaces. Autoimmune PAP (APAP) results from macrophage dysfunction caused by anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) autoantibodies, and the presence of antibodies more than the cutoff value is specific for APAP. In contrast, secondary PAP (SPAP) does not require anti-GM-CSF autoantibodies and is complicated by other diseases, including myelodysplastic syndrome (MDS). A 73-year-old man with anemia and thrombocytopenia was diagnosed with APAP and MDS simultaneously. The measurement of serum anti-GM-CSF autoantibodies is important for the correct diagnosis and management of PAP, even with an established diagnosis of underlying SPAP-suggestive disease.

Osteoblastic bone reaction in non-small cell lung cancer harboring epidermal growth factor receptor mutation treated with osimertinib.

BACKGROUND: Osteoblastic bone reaction (OBR) refers to an increase in bone density at the site of bone metastasis or the appearance of new sclerotic bone lesions after anticancer treatment. OBR can be misunderstood as disease progression. In this study, we aimed to investigate the prevalence and details of OBR and its association with clinical outcomes in patients with epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) treated with osimertinib. METHODS: This was a single-center, retrospective cohort study. We reviewed patients who were diagnosed with EGFR-mutant NSCLC with bone metastasis and received osimertinib as a first-line treatment between February 2018 and October 2022. The OBR was evaluated by comparing baseline computed tomography (CT) scans with the first CT scan after treatment initiation. RESULTS: A total of 45 patients were included in this study. Thirty-seven patients (82%) developed OBR. OBR developed in 94% (n = 16) of patients with sclerotic bone lesions (n = 17) at baseline. Similarly, OBR developed in lytic and mixed bone lesions in 76% and 82% of patients with lytic and mixed lesions, respectively. Progression-free survival (PFS) did not differ significantly between patients with (OBR group) and without OBR (non-OBR group) (median PFS, 24 months vs. 17 months; hazard ratio (HR), 0.62; 95% CI, 0.24-1.6; p = 0.31). In univariate analysis, the OBR group showed a trend toward longer skeletal-related events-free survival (SRE-FS) than the non-OBR group (median SRE-FS, 26 months vs. 12 months; HR, 0.53; 95% CI, 0.21-1.33; p = 0.16). Multivariate analysis showed OBR was a significant independent predictor of SRE-FS (HR, 0.35; 95% CI, 0.13-0.92; p = 0.034). CONCLUSIONS: OBR developed in most patients with NSCLC and bone metastasis who received osimertinib treatment. The increased incidence of OBR in patients with EGFR-mutant NSCLC with bone metastasis treated with osimertinib should not be confused with disease progression, and treatment decisions should be made carefully.

Left Vocal Cord Paralysis in Idiopathic Pleuroparenchymal Fibroelastosis: A Case Report.

Pleuroparenchymal fibroelastosis (PPFE) is a rare interstitial lung disease that is characterized by predominant upper lobe fibrosis and pleural thickening. In this report, we present an unusual case of idiopathic PPFE with left vocal cord paralysis that developed repeated aspiration pneumonia. Vocal cord paralysis is a rare complication of PPFE, and two mechanisms can be proposed: 1) Fibrous adhesion of the recurrent laryngeal nerve to the chest wall can cause stretching of the nerve. 2) Traction or compression of the recurrent laryngeal nerve due to the distortion of the tracheobronchial tree can cause paralysis of the vocal cord. Finally, to reduce the risk of aspiration pneumonia, laryngoscopic evaluation of the vocal cord is recommended in patients with PPFE with hoarseness and dysphagia for early intervention.

Pneumonitis associated with pembrolizumab plus chemotherapy for non-squamous non-small cell lung cancer.

Studies elucidating detailed characteristics of pneumonitis in association with chemo-immunotherapy are limited. We aimed to investigate the characteristics of images, prognostic factors, and clinical course of combination therapy associated with pneumonitis. A multicenter, retrospective cohort study of patients with non-squamous non-small cell lung cancer who received a combination of platinum, pemetrexed, and pembrolizumab was conducted. Patients with confirmed pneumonitis established by an independent multidisciplinary team were enrolled. For 53 patients with pneumonitis, radiographic features at diagnosis predominantly comprised an organizing pneumonia pattern (62%, 33/53). Twelve (23%) patients experienced a worsening respiratory status during pneumonitis management, which was associated with a high mortality rate (58%, 7/12) during treatment. Severe grade at pneumonitis diagnosis (p < 0.001), diffuse alveolar damage (DAD) pattern (p = 0.002), and disease extent ≥ 25% in the lungs (p = 0.009) were significantly associated with worsening respiratory status. Furthermore, post-diagnosis survival was significantly worse in severe pneumonitis (p = 0.02) than in mild and in patients with the DAD pattern than in those without (p < 0.0001). We showed detailed clinical course of patients with pneumonitis and reported several important influencing factors. Given the small number of trials on pneumonitis, our findings provide valuable information to guide the development of appropriate management guidelines and improve pneumonitis treatment.

Immune Checkpoint Inhibitor-Related Pneumonitis in Lung Cancer Patients with Interstitial Lung Disease: Significance of Radiological Pleuroparenchymal Fibroelastosis.

INTRODUCTION: Pleuroparenchymal fibroelastosis (PPFE) findings are associated with poor prognosis in interstitial lung disease (ILD). However, the effect of PPFE findings on the development of immune checkpoint inhibitor-related pneumonitis (ICI-pneumonitis), a life-threatening adverse event, in lung cancer patients with ILD has not been elucidated. We aimed to determine whether PPFE findings are a risk factor for ICI-pneumonitis in lung cancer patients with ILD. METHODS: We retrospectively examined 712 lung cancer patients, including 173 patients with background ILDs, who received ICI therapy in our institute between December 2015 and May 2021. Background ILDs were radiologically classified into three types: lone PPFE, other ILDs with PPFE, and other ILDs without PPFE. The cumulative ICI-pneumonitis incidence curves and median overall survival (mOS) were compared between the three radiological types, and risk factors for ICI-pneumonitis were evaluated. RESULTS: Of 173 eligible patients with ILD, 23 patients (13.3%) experienced ICI-pneumonitis. The Kaplan-Meier method and the log-rank test showed that lone PPFE patients had significantly lower incidence of ICI-pneumonitis (p = 0.024) and longer mOS (575 vs. 326 days; p = 0.0096) than other ILDs patients. ICI-pneumonitis (p = 0.35) and mOS (p = 0.29) were not significantly different between other ILDs with and without PPFE. A multivariate Cox proportional hazards regression analysis revealed that lone PPFE pattern was an independent predictive factor for ICI-pneumonitis (hazard ratio, 0.20; 95% confidence interval, 0.043-0.93; p = 0.040). CONCLUSION: ICI therapy could be safer in lone PPFE patients than in other ILDs patients with lung cancer.

Fibrotic Hypersensitivity Pneumonitis Diagnosed by a Re-evaluation with Bronchoalveolar Lavage at Disease Deterioration.

A 79-year-old man was admitted with worsening cough, dyspnea, and increased ground-glass opacity on chest computed tomography (CT). He had been diagnosed with idiopathic pulmonary fibrosis given the absence of an identifiable cause of interstitial pneumonia, chest CT findings, and absence of lymphocytosis in bronchoalveolar lavage (BAL) fluid. Meticulous history taking revealed extensive exposure to inciting antigens contained in chicken fertilizer before symptom worsening. A re-evaluation with BAL showed lymphocytosis, and clinical improvement with antigen avoidance confirmed the diagnosis of fibrotic hypersensitivity pneumonitis (fHP). A re-evaluation with BAL at disease deterioration after possible exposure to inciting antigen can facilitate a correct fHP diagnosis.

Safety and efficacy of osimertinib rechallenge or continuation after pneumonitis: A multicentre retrospective cohort study.

INTRODUCTION: Although osimertinib is a standard first-line treatment for patients with advanced-stage non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations, the incidence rate of pneumonitis associated with osimertinib is high. However, there are few reports about the safety and efficacy of osimertinib rechallenge after the development of pneumonitis. METHODS: We conducted a retrospective multicentre cohort study of consecutive patients who developed pneumonitis associated with osimertinib as a first-line and received osimertinib rechallenge. The primary outcome was the incidence rate of any grade pneumonitis after osimertinib rechallenge. The secondary outcome was treatment efficacy in patients after osimertinib rechallenge. RESULTS: In total, 33 patients who received osimertinib rechallenge were included. Of them, 26 patients had grade 1, 6 patients had grade 2, and 1 patient had grade 3 initial pneumonitis. The median follow-up period after the osimertinib rechallenge was 16.9 months (interquartile range, 11.1-21.3 months). After the start of osimertinib rechallenge, five patients (15%) experienced mild relapsed pneumonitis. Three of the five patients had similar imaging patterns for initial and relapsed pneumonitis. No significant differences in characteristics were observed between patients with and without relapsed pneumonitis. The median progression-free survival after osimertinib rechallenge was not achieved (95% confidence interval: 10.3 months - not reached). CONCLUSION: Osimertinib rechallenge was feasible and effective for patients who developed initial pneumonitis associated with first-line osimertinib therapy. Osimertinib might be considered a treatment option even after the development of mild initial pneumonitis.

Generalized lymphatic anomaly involving the pleura and bone in an older male: A case report.

Generalized lymphatic anomaly (GLA) is a congenital malformation of the lymphatic vessels that is often diagnosed in early childhood. Owing to the rarity and heterogeneity of its clinical course, GLA is frequently misdiagnosed, especially in adults. A 67-year-old man was incidentally found to have bone and pleural lesions. Multiple bone lesions detected on magnetic resonance images were mistaken for malignancy, and pathological evaluation led to the diagnosis of GLA. GLA should be considered in the differential diagnosis of multiple bone lesions, and a proactive biopsy to confirm the diagnosis may help avoid unnecessary invasive procedures.

Radiographic findings useful for diagnosis of primary chest wall lymphoma without preceding pleural disease: A case report.

A 70-year-old man with no history of pleural diseases had a dumbbell-shaped chest wall mass extending from the thoracic cavity to the spinal canal at the intervertebral foramen without bone destruction. Computed tomography revealed a positive a 'pleural sandwich sign', where the intercostal artery was enveloped by the mass. A high maximum standard uptake value was noted on fluorodeoxyglucose-positron emission tomography. No lesions were found in areas other than the chest wall. CT-guided biopsy was performed and he was diagnosed with primary chest wall lymphoma. This case report suggests that these radiographic findings may be helpful for diagnosing chest wall lymphomas even in patients without prior pleural disease.

Drug-Related Pneumonitis Induced by Osimertinib as First-Line Treatment for Epidermal Growth Factor Receptor Mutation-Positive Non-Small Cell Lung Cancer: A Real-World Setting.

BACKGROUND: Osimertinib has demonstrated impressive efficacy as a first-line treatment for patients with advanced epidermal growth factor receptor (EGFR) mutation-positive (m+) lung cancer. Drug-related pneumonitis (DRP) is a potentially lethal complication of osimertinib treatment, but reliable real-world data currently are lacking. RESEARCH QUESTION: What is the prevalence of osimertinib-induced DRP in first-line settings? What are the characteristics, clinical impact, and risk factors of osimertinib-induced DRP? STUDY DESIGN AND METHODS: We conducted a retrospective multicenter cohort study of patients who received osimertinib as a first-line treatment for advanced EGFR m+ non-small cell lung cancer (NSCLC) between August 2018 and December 2019. All chest CT scans and clinical information during osimertinib exposure were collected until June 2020. The primary end point was DRP incidence identified through central review. RESULTS: A total of 452 patients from 18 institutions were evaluated. Eighty patients (18%) had a diagnosis of DRP (all grades), and 21 patients (4.6%) had a diagnosis of grade 3 or more DRP. Among the patients with DRP, 46% were identified as having transient asymptomatic pulmonary opacity (TAPO). Regarding the CT scan patterns, organizing pneumonia, simple pulmonary eosinophilia, hypersensitivity pneumonia, diffuse alveolar damage, and nonspecific interstitial pneumonia were found in 30, 21, 18, 9, and two patients (38%, 26%, 23%, 11%, and 3%), respectively. In multivariate analysis, smoking history was identified as an independent risk factor for DRP (hazard ratio, 1.72; 95% CI, 1.01-2.89; P = .046). In the 3-month landmark analysis, DRP was associated with poor treatment efficacy; however, the presence of TAPO did not affect treatment efficacy negatively. INTERPRETATION: For osimertinib treatment in first-line settings, the frequency of DRP was considerably elevated to 18 %, and half of these patients exhibited TAPO features.

Development and external validation of a deep learning-based computed tomography classification system for COVID-19.

BACKGROUND: We aimed to develop and externally validate a novel machine learning model that can classify CT image findings as positive or negative for SARS-CoV-2 reverse transcription polymerase chain reaction (RT-PCR). METHODS: We used 2,928 images from a wide variety of case-control type data sources for the development and internal validation of the machine learning model. A total of 633 COVID-19 cases and 2,295 non-COVID-19 cases were included in the study. We randomly divided cases into training and tuning sets at a ratio of 8:2. For external validation, we used 893 images from 740 consecutive patients at 11 acute care hospitals suspected of having COVID-19 at the time of diagnosis. The dataset included 343 COVID-19 patients. The reference standard was RT-PCR. RESULTS: In external validation, the sensitivity and specificity of the model were 0.869 and 0.432, at the low-level cutoff, 0.724 and 0.721, at the high-level cutoff. Area under the receiver operating characteristic was 0.76. CONCLUSIONS: Our machine learning model exhibited a high sensitivity in external validation datasets and may assist physicians to rule out COVID-19 diagnosis in a timely manner at emergency departments. Further studies are warranted to improve model specificity.

Radiological pleuroparenchymal fibroelastosis-like lesion in idiopathic interstitial pneumonias.

BACKGROUND: Pleuroparenchymal fibroelastosis (PPFE) is characterised by predominant upper lobe pleural and subpleural lung parenchymal fibrosis. Radiological PPFE-like lesion has been associated with various types of interstitial lung diseases. However, the prevalence and clinical significance of radiological PPFE-like lesion in patients with idiopathic interstitial pneumonias (IIPs) are not fully understood. We aimed to determine the prevalence and clinical impact on survival of radiological PPFE-like lesion in patients with IIPs. METHODS: A post-hoc analysis was conducted using data from the Japanese nationwide cloud-based database of patients with IIPs. All the patients in the database were diagnosed as having IIPs by multidisciplinary discussion. Patients diagnosed with idiopathic PPFE were excluded. Clinical data and chest computed tomography (CT) image of 419 patients with IIPs were analysed. The presence of radiological PPFE-like lesion was independently evaluated by two chest radiologists blind to the clinical data. RESULTS: Of the 419 patients with IIPs, radiological PPFE-like lesions were detected in 101 (24.1%) patients, mainly in idiopathic pulmonary fibrosis (IPF) and unclassifiable IIPs, but less in idiopathic nonspecific interstitial pneumonia. Prognostic analyses revealed that radiological PPFE-like lesion was significantly associated with poor outcome in patients with IIPs, which was independent of age, IPF diagnosis and %FVC. In survival analyses, the patients with radiological PPFE-like lesions had poor survival compared with those without (log-rank, p < 0.0001). Subgroup analyses demonstrated that radiological PPFE-like lesion was significantly associated with poor survival both in patients with IPF and those with unclassifiable IIPs. CONCLUSION: Radiological PPFE-like lesion is a condition that could exist in IIPs, mainly in IPF and unclassifiable IIPs. Importantly, the radiological PPFE-like lesion is a non-invasive marker to predict poor outcome in patients with IIPs, which should be carefully considered in clinical practice.

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

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

Impact of bronchoalveolar lavage lymphocytosis on the effects of anti-inflammatory therapy in idiopathic non-specific interstitial pneumonia, idiopathic pleuroparenchymal fibroelastosis, and unclassifiable idiopathic interstitial pneumonia.

BACKGROUND: Idiopathic non-specific interstitial pneumonia (iNSIP), idiopathic pleuroparenchymal fibroelastosis (iPPFE), and unclassifiable idiopathic interstitial pneumonia (IIP) are IIPs with chronic fibrotic phenotypes, and unlike idiopathic pulmonary fibrosis, they have often been treated with anti-inflammatory drugs, including corticosteroids and immunosuppressants. However, the impact of bronchoalveolar lavage (BAL) lymphocytosis on the effects of anti-inflammatory therapy has never been evaluated. This study aimed to elucidate whether BAL lymphocytosis can be used to predict the efficacy of anti-inflammatory drugs for iNSIP, iPPFE, and unclassifiable IIP. METHODS: Japanese patients diagnosed with iNSIP, iPPFE, and unclassifiable IIP by multidisciplinary discussion were identified using the nationwide registry. Eligible patients were stratified into four groups with and without BAL lymphocytosis and anti-inflammatory therapy to compare overall survival (OS) and changes in lung function. BAL lymphocytosis was defined as a lymphocyte differential count > 15%, and the cut-off was corroborated by survival classification and regression tree analysis. RESULTS: Overall, 186 patients (37 iNSIP, 16 iPPFE, and 133 unclassifiable IIP) were analyzed. Limited to patients treated with anti-inflammatory drugs (n = 123), patients with BAL lymphocytosis had a better prognosis [hazard ratio (HR), 0.26; 95% confidence interval (CI), 0.11-0.63; P = 0.003], higher slope of forced vital capacity (FVC) % predicted for 2 years, and longer OS (log-rank test, P = 0.012) than those without BAL lymphocytosis. On multivariate analysis, BAL lymphocytosis (HR 0.31; 95% CI 0.13-0.75; P = 0.009) was a prognostic factor for OS, along with age and FVC % predicted. Conversely, for patients managed without anti-inflammatory therapy (n = 63), the presence or absence of BAL lymphocytosis had no prognostic value. CONCLUSIONS: BAL lymphocytosis is associated with good outcomes in patients treated with anti-inflammatory drugs, but has no prognostic value when anti-inflammatory drugs are not used. BAL lymphocytosis may provide a predictive biomarker for identifying patients with iNSIP, iPPFE and unclassifiable IIP who are likely to benefit from anti-inflammatory drugs.

Histologic factors associated with nintedanib efficacy in patients with idiopathic pulmonary fibrosis.

BACKGROUND: Histopathologic factors predictive of nintedanib efficacy in idiopathic pulmonary fibrosis have not been studied. We aimed to describe the characteristics, focusing on histopathology, of idiopathic pulmonary fibrosis patients who did and did not respond to nintedanib. METHODS: This study retrospectively examined the clinicoradiopathologic features of 40 consecutive patients with surgical lung biopsy-confirmed idiopathic pulmonary fibrosis treated with nintedanib. Additionally, we compared the histopathologic scoring of 21 microscopic features between patients with functional or radiological progression and those with non-progression during 12 months of treatment. RESULTS: The histopathologic evaluation showed edematous changes in the interlobular septum as the only histologic finding observed more frequently in patients with both functional and radiological progression than in those without (58% vs. 14%, P = 0.007 and 50% vs. 0%, P = 0.003, respectively). Regarding per-year change, patients with edematous changes in the interlobular septum showed greater progression in median changes in spared area (-12%, interquartile range: [-25%--5%], vs. -3% [-7%-0%], P = 0.004) and reticular shadow (7% [3%-13%], vs. 0% [0%-5%], P = 0.041) on computed tomography. Functional and radiological progression-free survival were shorter in patients with edematous changes in the interlobular septum than in those without (6.6 months, 95% confidence interval: [5.9-25.3], vs. event <50%, [12.1-Not available], P = 0.0009, and 6.1 months, [5.2-6.6] vs. 14.5 months [7.8-not available], P<0.0001). CONCLUSIONS: Edematous changes in the interlobular septum may indicate poor nintedanib efficacy in idiopathic pulmonary fibrosis. Further studies are needed to validate these findings and address the mechanism behind ECIS.

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.

Influenza H1N1 virus-associated pneumonia often resembles rapidly progressive interstitial lung disease seen in collagen vascular diseases and COVID-19 pneumonia; CT-pathologic correlation in 24 patients.

PURPOSE: To describe computed tomography (CT) findings of influenza H1N1 virus-associated pneumonia (IH1N1VAP), and to correlate CT findings to pathological ones. METHODS: The study included 24 patients with IH1N1VAP. Two observers independently evaluated the presence, distribution, and extent of CT findings. CT features were divided into either classical form (C-form) or non-classical form (NC-form). C-form included: A.) broncho-bronchiolitis and bronchopneumonia type, whereas NC-forms included: B.) diffuse peribronchovascular type, simulating subacute rheumatoid arthritis-associated (RA) interstitial lung disease (ILD) and C.) lower peripheral and/or peribronchovascular type, resembling dermatomyositis-associated ILD and COVID-19 pneumonia. In 10 cases with IH1N1VAP where lung biopsy was performed, CT and pathology findings were correlated. RESULTS: The most common CT findings were ground-glass opacities (24/24, 100 %) and airspace consolidation (23/24, 96 %). C-form was found in 11 (46 %) patients while NC-form in 13 (54 %). Types A, B, and C were seen in 11(46 %), 4 (17 %), and 9 (38 %) patients, respectively. The lung biopsy revealed organizing pneumonia in all patients and 6 patients (60 %) showed incorporated type organizing pneumonia that was common histological findings of rapidly progressive ILD. CONCLUSION: In almost half of patients of IH1N1VAP, CT images show NC-form pneumonia pattern resembling either acute or subacute RA or dermatomyositis-associated ILD and COVID-19 pneumonia.