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M. Furuya (1); R. Tanaka (2); K. Okudela (3); S. Nakamura (4); R. Shibuya (5); T. Tsuzuki (6); Y. Nakatani. (7) Departments of (1) Molecular Pathology and (3) Pathology, Yokohama [...], Context: Birt-Hogg-Dube; syndrome (BHDS) is an inherited disorder caused by genetic mutations of folliculin (FLCN). Individuals with BHDS have multiple pulmonary cysts and skin papules, and they are at high risk for developing renal cell carcinomas. Currently, little is known about whether patients with BHDS are predisposed to develop neoplasms in organs other than the kidney. Design: In this study, we describe 12 neoplastic pulmonary lesions in 5 patients from our database of 270 patients with BHDS. The histopathologic types of the surgically resected neoplasms included adenocarcinoma in situ (n = 1), papillary adenocarcinoma (n = 1), micropapillary adenocarcinoma (n = 1), atypical adenomatous hyperplasia (n = 8), and micronodular pneumocyte hyperplasia (MPH)-like lesion (n = 1). These lesions were microdissected, and possible somatic events of FLCN were investigated. Immunostaining with mutation specific antibodies against epidermal growth factor receptor (EGFR) and antibodies against mTOR pathway molecules was also performed. Results: The 1 MPH-like lesion showed loss of heterozygosity (LOH) of FLCN, whereas none of the adenocarcinomas showed LOH. Two adenocarcinomas were positively immunostained for mutation-specific EGFR. All lesions except the MPH-like lesion were strongly immunostained for phospho-mTOR and phospho-S6. Conclusions: Individuals with BHDs are at risk for various pulmonary neoplasms of pneumocyte lineage; LOH of FLCN may be related to the development of the MPH-like lesion, whereas further study is necessary to determine whether any cross-talk between activated EGFR and mTOR pathways under the haploinsufficient condition of folliculin may underlie the development of adenocarcinomas.

Abstract Introduction Lambert–Eaton myasthenic syndrome is a rare disorder and it is known as a paraneoplastic neurological syndrome. Small cell lung cancer often accompanies this syndrome. Lambert–Eaton myasthenic syndrome associated with lung adenocarcinoma is extremely rare; there are only a few reported cases worldwide. Case presentation A 75-year-old Japanese man with a past history of chronic rheumatoid arthritis and Sjögren syndrome was diagnosed with Lambert–Eaton myasthenic syndrome by electromyography and serum anti-P/Q-type voltage-gated calcium channel antibody level preceding the diagnosis of lung cancer. A chest computed tomography to screen for malignant lesions revealed an abnormal shadow in the lung. Although a histopathological examination by bronchoscopic study could not reveal the malignancy, lung cancer was mostly suspected after the results of a chest computed tomography and [18F]-fluorodeoxyglucose positron emission tomography. An intraoperative diagnosis based on the frozen section obtained by tumor biopsy was adenocarcinoma so the patient underwent a lobectomy of the right lower lobe and lymph node dissection with video-assisted thoracoscopic surgery. The permanent pathological examination was the same as the frozen diagnosis (pT2aN1M0: Stage IIa: TNM staging 7th edition). Immunohistochemistry revealed that most of the cancer cells were positive for P/Q-type voltage-gated calcium channel. Conclusions Our case is a rare combination of Lambert–Eaton myasthenic syndrome associated with lung adenocarcinoma, rheumatoid arthritis and Sjögren syndrome, and to the best of our knowledge it is the first report that indicates the presence of voltage-gated calcium channel in lung adenocarcinoma by immunostaining.

Purpose: We aimed to identify computed tomography (CT) radiomics features that are associated with cellular infiltration and construct CT radiomics models predictive of cellular infiltration in patients with fibrotic ILD., Materials and Methods: CT images of patients with ILD who underwent surgical lung biopsy (SLB) were analyzed. Radiomics features were extracted using artificial intelligence-based software and PyRadiomics. We constructed a model predicting cell counts in histological specimens, and another model predicting two classifications of higher or lower cellularity. We tested these models using external validation., Results: Overall, 100 patients (mean age: 62 ± 8.9 [standard deviation] years; 61 men) were included. The CT radiomics model used to predict cell count in 140 histological specimens predicted the actual cell count in 59 external validation specimens (root-mean-square error: 0.797). The two-classification model's accuracy was 70% and the F1 score was 0.73 in the external validation dataset including 30 patients., Conclusion: The CT radiomics-based model developed in this study provided useful information regarding the cellular infiltration in the ILD with good correlation with SLB specimens., (© 2024. The Author(s).)

We herein report a case of bilateral pneumothorax after a unilateral transbronchial lung cryobiopsy (TBLC). A 73-year-old man with no history of cardiothoracic surgery underwent a TBLC for the reevaluation of interstitial lung disease. Five hours later, he developed bilateral pneumothorax, pneumomediastinum, and subcutaneous emphysema. He underwent bilateral chest drainage and was discharged 18 days later. The lung biopsy specimens obtained from the TBLC contained visceral pleura and bronchial cartilage, suggesting bronchial injury as the cause of the bilateral pneumothorax.

Objectives: Metachronous lung cancer arising after resection of non-small-cell lung cancer is either a second primary lung cancer (SPLC) or intrapulmonary metastasis (IPM) of the initial lung cancer; however, differential diagnosis is difficult. We evaluated the surgical outcomes of metachronous lung cancer in a combined population of patients with SPLC and IPM., Methods: A retrospective study of 3534 consecutive patients with resected non-small-cell lung cancer between 1992 and 2016 was conducted at 4 institutions., Results: A total of 105 patients (66 males; median age, 70 years) who underwent a second pulmonary resection for metachronous lung cancer were included. Most patients (81%) underwent sublobar resection, and there was no 30-day mortality. All metachronous lung cancers were cN0, 5 were pN1-2. The postoperative comprehensive histologic assessment revealed SPLC (n = 77) and IPM (n = 28). The 5-year overall survival rate after the second resection was 70.6% (median follow-up: 69.7 months). A multivariable analysis showed that age >70 years at the second resection (P = 0.013), male sex (P = 0.003), lymph node involvement in metachronous cancer (P < 0.001), pathological invasive size of metachronous cancer >15 mm (P < 0.001) and overlapping squamous cell carcinoma histology of the initial and metachronous cancers (P = 0.003) were significant prognostic factors for poor survival after the second resection, whereas histological IPM was not (P = 0.065)., Conclusions: Surgery for cN0 metachronous lung cancer is safe and shows good outcomes. There were no statistically significant differences in the SPLC and IPM results. Caution should be exercised when operating on patients with overlapping squamous cell carcinoma., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery.)

Background: Idiopathic multicentric Castleman disease (iMCD) is a rare polyclonal lymphoproliferative disease often associated with pulmonary involvement. Recently, transbronchial lung cryobiopsy (TBLC) has been reported to be useful for the diagnosis of diffuse interstitial lung disease. However, there have been no reports of pathological assessment of TBLC for iMCD., Method: To clarify the efficacy of TBLC in the diagnosis of iMCD, we retrospectively reviewed four iMCD patients who had undergone both TBLC and surgical lung biopsy (SLB)., Results: The median age was 44 years; 2 males and 2 females. Two or three TBLC specimens were taken from each patient. All patients had no complications other than minimal bleeding. The size of the TBLC specimens was approximately 5-6 × 3-4 mm, and the alveolar region, and centrilobular and perilobular areas were adequately sampled. As with SLB, the extent of lung lesions and inflammatory cell infiltration could be sufficiently evaluated by TBLC. The presence of lymphoid follicles could also be assessed by TBLC; however, the germinal centers with lymphoid follicles were difficult to evaluate. The TBLC specimens could also be evaluated for immunostaining, especially IgG4 immunostaining, to rule out IgG4-related lung disease. Pulmonary pathological grading showed a high concordance rate between major pathological findings of TBLC and SLB. The pathologist's confidence level of TBLC for the diagnosis of iMCD was high in all cases., Conclusions: TBLC exhibits a high concordance rate with SLB in the pathological evaluation of iMCD, which may be useful for the diagnosis of iMCD., Competing Interests: Conflict of Interest The authors have no conflicts of interest., (Copyright © 2023. Published by Elsevier B.V.)

Background: Upper-lung field pulmonary fibrosis (upper-PF), radiologically consistent with pleuroparenchymal fibroelastosis (PPFE), was reported to develop in patients with a history of asbestos exposure and tuberculous pleurisy, indicating that chronic pleuritis is correlated with upper-PF development. Round atelectasis reportedly emerges after chronic pleuritis. This study aimed to clarify the association between round atelectasis and upper-PF., Methods: We examined the radiological reports of all consecutive patients with round atelectasis between 2006 and 2018 and investigated the incidence of upper-PF development., Results: Among 85 patients with round atelectasis, 21 patients (24.7%) were confirmed to finally develop upper-PF lesions. Upper-PF was diagnosed after round atelectasis recognition in more than half of the patients (13/21, 61.9%), whereas upper-PF and round atelectasis were simultaneously detected in the remaining 8 patients. At the time of round atelectasis detection, almost all patients (19/21, 90.5%) had diffuse pleural thickening and round atelectasis was commonly observed in non-upper lobes of 19 patients (90.5%). Fourteen patients had round atelectasis in unilateral lung, and the remaining 7 patients had round atelectasis in bilateral lungs. Among all 14 patients with unilateral round atelectasis, upper-PF developed on the same (n = 11) or both sides (n = 3). Thus, upper-PF emerged on the same side where round atelectasis was present (14/14, 100%). The autopsy of one patient revealed a thickened parietal-visceral pleura suggestive of chronic pleuritis. Subpleural fibroelastosis was also observed., Conclusions: Upper-PF occasionally develops on the same side of round atelectasis. Upper-PF may develop as a sequela of chronic pleuritis., Competing Interests: Conflict of Interest The authors have no conflicts of interest., (Copyright © 2023 The Japanese Respiratory Society. Published by Elsevier B.V. All rights reserved.)

Pulmonary complications after liver transplantation are common in the postoperative period, becoming less frequent in the subsequent months, and rare after 1 year. However, we encountered two cases of very-late-onset interstitial pneumonia suspected to be related to liver transplantation after 14 and 15 years. Both patients presented with non-specific interstitial pneumonia patterns, which significantly improved with corticosteroid therapy. Physicians should be aware of such complications and monitor them after liver transplantation., Competing Interests: Conflict of Interest The authors have no conflicts of interest., (Copyright © 2023 The Japanese Respiratory Society. Published by Elsevier B.V. All rights reserved.)

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., (© 2023. The Author(s).)

Background: Small cell lung cancer (SCLC) is a neuroendocrine tumor with poor prognosis. Neuroendocrine tumors possess characteristics of both nerve cells and hormone-secreting cells; therefore, targeting the neuronal properties of these tumors may lead to the development of new therapeutic options. Among the endogenous signaling pathways in the nervous system, targeting the glutamate pathway may be a useful strategy for glioblastoma treatment. Perampanel, an antagonist of the synaptic glutamate α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR), has been reported to be effective in patients with glioblastoma. In this study, we aimed to investigate the antitumor effects of AMPAR antagonists in human SCLC cell lines., Methods: We performed to examine the expression of AMPAR using Western blot and immunohistochemical analysis. The antitumor effects of AMPAR antagonists on human SCLC cell lines were investigated in vitro and in vivo. We also analyzed the signaling pathway of AMPAR antagonists in SCLC cell lines. Statistical analysis was performed by the GraphPad Prism 6 software., Results: We first examined the expression of endogenous AMPAR in six human SCLC cell lines, detecting AMPAR proteins in all of them. Next, we tested the anti-proliferative effect of two AMPAR antagonists, talampanel and cyanquixaline, using SCLC cells in vitro and in vivo. Both AMPAR antagonists inhibited cell proliferation and mitogen-activated protein kinase (MAPK) phosphorylation in SCLC cells in vitro. Further, we observed reduced proliferation of implanted cell lines in an in vivo setting, assessed by Ki-67 immunohistochemistry. Additionally, using immunohistochemical analysis we confirmed AMPAR protein expression in human SCLC samples., Conclusion: AMPAR may be a potential therapeutic target for SCLC., (© 2023 The Authors. Thoracic Cancer published by China Lung Oncology Group and John Wiley & Sons Australia, Ltd.)

We present a case of lung carcinoma with a unique biphasic feature. The patient was a 67-year-old male smoker with idiopathic pulmonary fibrosis (IPF). A subpleural tumor in the left lower lobe, embedded in fibrotic tissue, was resected. Histologically, the tumor consisted of major and minor components of mucoepidermoid carcinoma (MEC) and surrounding conventional lepidic adenocarcinoma, respectively. Both components had the same TP53 somatic mutation (p.V157F) but not Mastermind-like 2 (MAML2) gene rearrangement. The two components may have developed from an identical origin. The tumor could be trans-differentiating from lepidic adenocarcinoma to MEC, possibly promoted by IPF-induced tissue damage. The final diagnosis was "adenosquamous carcinoma with mucoepidermoid-like features (that may originate from lepidic adenocarcinoma)." This case has implications for the potential histogenesis of peripheral lung MEC. Over time, the MEC would expand and outgrow the lepidic adenocarcinoma, making it impossible to distinguish between fake and true MEC. The present case suggests that peripheral MEC could differ from proximal MEC in its histogenesis and molecular genetics. Thus, careful examination is necessary to diagnose peripheral lung MEC, particularly in patients with interstitial lung diseases., (© 2023 Japanese Society of Pathology and John Wiley & Sons Australia, Ltd.)

Background: The diagnostic accuracy and safety of transbronchial lung cryobiopsy (TBLC) via a flexible bronchoscope under sedation compared with that of surgical lung biopsy (SLB) in the same patients is unknown., Methods: Retrospectively the data of fifty-two patients with interstitial lung diseases (median age: 63.5 years; 21 auto-antibody positive) who underwent TBLC followed by SLB (median time from TBLC to SLB: 57 days) was collected. The samples from TBLC and SLB were randomly labelled to mask the relationship between the two samples. Diagnosis was made independently by pathologists, radiologists, and pulmonary physicians in a stepwise manner, and a final diagnosis was made at multidisciplinary discussion (MDD). In each diagnostic step the specific diagnosis, the diagnostic confidence level, idiopathic pulmonary fibrosis (IPF) diagnostic guideline criteria, and treatment strategy were recorded., Results: Without clinical and radiological information, the agreement between the histological diagnoses by TBLC and SLB was 42.3% (kappa [κ] = 0.23, 95% confidence interval [CI]: 0.08-0.39). However, the agreement between the TBLC-MDD and SLB-MDD diagnoses and IPF/non-IPF diagnosis using the two biopsy methods was 65.4% (κ = 0.57, 95% CI: 0.42-0.73) and 90.4% (47/52), respectively. Out of 38 (73.1%) cases diagnosed with high or definite confidence at TBLC-MDD, 29 had concordant SLB-MDD diagnoses (agreement: 76.3%, κ = 0.71, 95% CI: 0.55-0.87), and the agreement for IPF/non-IPF diagnoses was 97.4% (37/38). By adding the pathological diagnosis, the inter-observer agreement of clinical diagnosis improved from κ = 0.22 to κ = 0.42 for TBLC and from κ = 0.27 to κ = 0.38 for SLB, and the prevalence of high or definite diagnostic confidence improved from 23.0% to 73.0% and from 17.3% to 73.0%, respectively. Of all 383 TBLC performed during the same period, pneumothorax occurred in 5.0% of cases, and no severe bleeding, acute exacerbation of interstitial lung disease, or fatal event was observed., Conclusions: TBLC via a flexible bronchoscope under deep sedation is safely performed, and the TBLC-MDD diagnosis with a high or definite confidence level is concordant with the SLB-MDD diagnosis in the same patients., (© 2023. The Author(s).)

Objective Interstitial lung disease (ILD) is the most critical manifestation in patients with rheumatoid arthritis (RA). In some cases, ILD may appear before the RA onset. Some patients with an initial diagnosis of idiopathic interstitial pneumonia (IIPs) develop RA; however, few studies have reported on its features, and the details remain unknown. In the present study, the clinical, radiological, and pathological features were evaluated in patients with ILD preceding RA. Methods The clinical, radiological, and pathological features of patients with ILD preceding RA were retrospectively reviewed using the medical records. Patients Ten patients with ILD preceding RA out of 883 IIP patients who underwent a surgical lung biopsy at our hospital from 2004 to 2018 were retrospectively examined. Results The median patient age was 59 (range 50-76) years old, and 7 of the patients were women. The median time from the ILD diagnosis to the RA onset was 50 (range 33-65) months. Regarding the high-resolution computed tomography pattern, the "indeterminate for UIP" pattern was the most popular, and cysts were seen in all cases. Attenuation around the cyst was prominent. Pathological findings showed plasma cell infiltration, bronchus-associated lymphoid tissue (BALT), and bronchiolitis in the lobules. Cellular and destructive bronchiolitis was noticeable in many patients with ILD preceding RA and contributed to the destruction and dilation of the bronchiole. Conclusion In ILD patients with IIP, radiological and pathological findings with increased attenuation around the cysts, prominent inflammatory cell infiltration (especially in plasma cells), an increase in the BALT number, and cellular and destructive bronchiolitis might serve as helpful RA development indicators.

Aims: In COVID-19 pneumonia, early detection and appropriate treatment are essential to prevent severe exacerbation. Therefore, it is important to understand the initiating events of COVID-19 pneumonia. However, at present, the literature about early stage disease has been very limited. Here, we investigated the earliest histopathological changes and gene expression profiles associated with COVID-19 pneumonia., Methods and Results: We carefully examined 25 autopsied cases with different clinical courses. Dilation of capillaries and edematous thickening of the alveolar septa were found even in areas that macroscopically looked almost normal. Pneumocytes, histocytes/macrophages, and vascular endothelial cells were immunohistochemically positive for tissue factor, which is an important early responder to tissue injuries. Comprehensive gene expression analyses revealed that those lesions presented differential profiles compared to those of control lungs and were associated with a significant upregulation of the lysosomal pathway., Conclusions: Alveolar capillary dilation and edematous thickening may be the earliest histopathological change detected in COVID-19 pneumonia. Intensive investigations of such lesions may lead to an understanding of the initiating event of not only COVID-19 pneumonia but also of general diffuse alveolar damage., (©The Author(s) 2023. Open Access. This article is licensed under a Creative Commons CC-BY International License.)

Patients with non-small cell lung cancer (NSCLC) are often positive for oncogenic driver mutations, such as EGFR, ALK, BRAF, RET and MET exon 14 skipping mutations (METex14 skipping). Recently, METex14 skipping has become a functional biomarker for NSCLC with the approval of MET kinase inhibitors. Tepotinib is an oral MET kinase inhibitor. Its overall response rate is 46%, and the median duration of the response is 11.1 months. In Japan, companion diagnostics for tepotinib are limited with the ArcherMET and AmoyDx test, but not with Oncomine Dx target test. The present study reports the case of a 60-year-old male patient with lung adenocarcinoma harboring METex14 skipping, which was positive on Oncomine DxTT, but not on ArcherMET. In his sample used for Oncomine DxTT, the read count of MET(13)-MET(15) products was only 46. He was treated with various chemotherapeutic agents, but developed cardiac tamponade due to the progression of the disease of mediastinal lymph node metastases. Tepotinib was administered following pericardial drainage, resulting in an immediate response in all lesions. The majority of the discordant samples between Oncomine DxTT and ArcherMET had read counts <800, and the patient described herein had only 46. Therefore, the results of the present study indicate that the use of tepotinib should be considered even in patients whose METex14 skipping results were negative with ArcherMET, yet positive on Oncomine DxTT, particularly relatively with low lead counts., Competing Interests: TB has received consultation fees from Merck Pharma Japan (the supplier of tepotinib distributed in Japan). All remaining authors declare that they have no competing interests., (Copyright © 2020, Spandidos Publications.)

Introduction: Idiopathic multicentric Castleman disease (MCD) has been reported to form lung cysts at a relatively high rate. However, the radiological and pathological features of cystic formation in MCD are unclear., Methods: To clarify these questions, we retrospectively investigated the radiological and pathological findings of cysts in MCD patients. Eight consecutive patients who underwent surgical lung biopsies in our center from 2000 to 2019 were included., Results: The median age was 44.5 years, with three males and five females. On the initial computed tomography, cyst formation was found in seven patients (87.5%). All of the cysts were multiple, round, and thin walled, accompanying ground-glass attenuation (GGA) around cysts. In six patients (75%), cysts increased during their clinical courses, and the new cysts had emerged from GGA, although GGA was improved by treatment. In all four cases, whose pulmonary cysts could be pathologically evaluated, a marked plasma cell infiltration around the cyst wall, and loss of elastic fibers of the alveolar wall were observed., Conclusions: Pulmonary cysts emerged in the area of GGA pathologically consistent with plasma cell infiltration. Cysts in MCD may be formed by the loss of elastic fibers due to marked plasma cell infiltration and may be considered irreversible changes.

Background: The cytological features of interstitial pneumonia (IP)-related lung adenocarcinoma (LADC) have not been clearly described. This study aimed to describe its cytomorphological features, uncover potential problems in practical cytological diagnosis, and provide possible solutions., Methods: Bronchial brushing cytology samples from 40 IP-related LADC cases (the IP group) and 110 control cases (LADC unrelated to IP; the non-IP group) were analyzed. All patients underwent surgery after brushing cytology, and their histopathological subtypes were determined. The authors reviewed the cytological features and focused particularly on cytoplasmic mucin production., Results: In the IP group, neoplastic cells with cytoplasmic mucin were detected at a significantly higher frequency (44.4% [8 of 18] vs. 6.3% [4 of 64]), and most of them were invasive mucinous adenocarcinomas (IMAs). Twenty-two of the 40 LADC cases in the IP group failed to be judged as "malignant/positive" (thus, they were judged to be "equivocal and/or negative"). The frequency of equivocal and/or negative judgments was 55.0% (22 of 40) in the IP group and 41.8% (46 of 110) in the non-IP group. The cytological diagnosis of IMA was difficult because it showed only slight nuclear atypia. Therefore, the authors examined the immunocytochemical expression of hepatocyte nuclear factor 4α (HNF4α), a diagnostic marker for IMA. As a result, four of the six cases that were judged to be equivocal in the IP group showed positive signals and could be retrospectively judged as malignant/positive., Conclusions: The cytological diagnosis of IP-related LADC may be more difficult because of the larger proportion of IMA. Immunocytochemistry for HNF4α can be used to improve diagnostic confidence in IP-related LADC., (© 2022 American Cancer Society.)

Introduction: The accuracy of serum immunoglobulin (Ig) G testing for diagnosis of stable bird-related fibrotic hypersensitivity pneumonitis (HP) is controversial. Furthermore, avian serum, extracts, or feathers were employed as antigens in bird-related HP; however, the usage of egg whites has not been reported. We investigated the utility of IgG testing against pigeon egg whites in patients with stable bird-related fibrotic HP., Methods: Patients having a positive inhalation test for pigeon antigen and a histological investigation with diagnostic confidence of fibrotic HP greater than moderate confidence were included. The control group consisted of patients with interstitial lung diseases (ILDs) other than HP. To select patients in the stable phase, patients with fibrotic HP were excluded if they were clinically considered to be in the acute exacerbation or acute phase. The IgG testing against pigeon egg whites by enzyme-linked immunosorbent assay and the commercialized anti-pigeon IgG testing by fluorescence enzyme immunoassay were investigated., Results: In this study, 37 patients with stable bird-related fibrotic HP and 32 patients with ILDs other than HP participated. Serum IgG testing for pigeon egg whites revealed that the control group's optical density was 0.147 and the group with bird-related fibrotic HP had a mean value of 0.207 (p = 0.011). IgG testing in bronchial alveolar lavage fluid was not significantly higher in the bird-related fibrotic HP group than in controls (p = 0.42). No significant difference in area under the curve between an IgG testing against pigeon egg whites and a commercialized anti-pigeon IgG testing was observed (p = 0.24). Test accuracy for stable bird-related fibrotic HP ranged from 62% to 76% sensitivity and 59-66% specificity., Conclusion: IgG testing to identify the inciting antigen in patients with stable bird-related fibrotic HP had relatively low accuracy., (© 2023 S. Karger AG, Basel.)

Immunohistochemical analysis of formalin-fixed paraffin-embedded (FFPE) tissue blocks is routinely used to identify virus-infected cells. However, detecting virus particles in FFPE sections using light microscopy is difficult because of the light diffraction resolution limitations of an optical microscope. In this study, light microscopy and field emission scanning electron microscopy were performed to observe 3-dimensional virus particles in FFPE sections in a nondestructive manner using NanoSuit or osmium conductive treatment methods. The virus particles in FFPE sections were immunostained with specific antibodies against the surface antigens of the viral particles and stained with 3,3'-diaminobenzidine. A metal solution (0.2% gold chloride or 2% osmium tetroxide) was applied to enhance the 3,3'-diaminobenzidine-stained area. This procedure is nondestructive for FFPE sections and is a simpler method than transmission electron microscopy. To validate the applicability of this technique, we performed 3-dimensional imaging of the virus particles of different sizes, such as human papillomavirus, cytomegalovirus, and varicella-zoster virus. Furthermore, ultrathin sections from the FFPE sections that were observed to harbor viral particles using field emission scanning electron microscopy were prepared and assessed using transmission electron microscopy. In the correlative areas, transmission electron microscopy confirmed the presence of large numbers of virus particles. These results indicated that the combination of marking viral particles with 3,3'-diaminobenzidine/metal staining and conductive treatment can identify active progeny virus particles in FFPE sections using scanning electron microscopy. This easy correlative imaging of field emission scanning electron microscopy of the identical area of FFPE in light microscopy may help elucidate new pathological mechanisms of virus-related diseases., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

A 61-year-old patient with cystic bronchiectasis and bronchial artery hyperplasia in the left lung was diagnosed with polymyositis-related interstitial lung disease. After nine months of immunosuppressive therapy, he developed unilateral autoimmune pulmonary alveolar proteinosis (APAP) in the right lung with respiratory failure. After bronchial artery embolization to prevent massive hemoptysis, whole-lung lavage was performed using veno-venous extracorporeal membrane oxygenation. His respiratory condition improved, and he was discharged from the hospital with supplemental oxygen. Three reported cases of APAP with polymyositis-related interstitial lung disease, including the present case, were all positive for anti-glycyl tRNA synthetase antibody and were under immunosuppressive treatment.

Objectives: Pleuroparenchymal fibroelastosis (PPFE) is a rare idiopathic interstitial pneumonia characterized by pleural-parenchymal involvement, predominantly in the upper lobes. Unilateral upper lung field pulmonary fibrosis (upper-PF) that is radiologically consistent with PPFE reportedly develops after lung cancer surgery in the operated side and presents many clinical characteristics in common with PPFE. However, the incidence and perioperative associated factors remain unclear., Methods: All consecutive patients with lung cancer resected completely from 2008 to 2016 were investigated retrospectively. Pre-/postoperative characteristics were compared between patients with and without unilateral upper-PF. Cumulative incidence curves were estimated using competing risk analysis., Results: Among the 587 included patients, 25 patients (4.3%) were diagnosed as unilateral upper-PF. The 3-, 5- and 10-year cumulative incidence of unilateral upper-PF was 2.3%, 3.3% and 5.3%, respectively. In multivariable analysis, male sex, presence of a pulmonary apical cap, lobar resection and low % vital capacity (%VC < 80%) were independent perioperative associated factors. The 10-year cumulative incidence was 6.3% in patients treated with lobar resection, 8.0% in male patients, 10.3% in patients with pulmonary apical cap and 14.5% in patients with low %VC. Postoperative pleural effusion at 6 months after surgery was much more common in the patients who later developed unilateral upper-PF (96.0% vs 24.2%). This pleural effusion persisted and was accompanied thereafter by pleural thickening and subpleural pulmonary fibrosis. During the clinical courses of 25 patients with unilateral upper-PF, 18 patients presented symptoms related to upper-PF and 6 patients died., Conclusions: Unilateral upper-PF is an occasional but under-recognized late complication after lung cancer surgery., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery.)

Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge 1-5 . Here we conducted a genome-wide association study (GWAS) involving 2,393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3,289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target., (© 2022. The Author(s).)

We report the first case with COVID-19-like acute respiratory distress syndrome after mRNA-1273 SARS-CoV-2 vaccination. An 88-year-old woman developed dyspnea several hours after vaccination with the second dose of mRNA-1273. She was hospitalized on day nine due to worsening dyspnea. Chest computed tomography showed bilateral ground-glass opacities and consolidations, mainly in the peripheral lung areas. Repeat polymerase chain reaction tests for SARS-CoV-2 were negative, although the serum level of antibodies against spike protein was extremely elevated. Her condition did not improve with high-dose corticosteroids and high-flow nasal cannula oxygen therapy; she died on day 18. Autopsy findings revealed very early-phase diffuse alveolar damage in the whole lung without other lung diseases. The clinical and pathological findings suggested vaccine-induced acute respiratory distress syndrome. Serological and pathological tests might be useful to differentiate the disease from COVID-19., Competing Interests: Conflict of Interest Department of Infectious Disease and Respiratory Medicine of Yokohama Municipal Citizen's Hospital, to which Yukihiro Yoshimura, Hiroaki Sasaki, Nobuyuki Miyata, Kazuhito Miyazaki, and Natsuo Tachikawa belong, have received research funding from three companies, Gilead Sciences, Inc., Eli Lilly Japan K.K, and Ono Pharmaceutical Co., Ltd. in the last two years., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Glutaraldehyde (GA)-fixed autologous tissues, including the pericardium, are widely used as patches and valve substitutes in cardiovascular surgery. However, GA treatment causes tissue calcification. No rapid anticalcification method has been established for use during surgery. Here, we aimed to establish a rapid anticalcification method using ethanol, as has already been demonstrated for bioprosthetic valves., Methods: Thoracic aorta tissues were first fixed with GA for 3 min and then treated with ethanol for 0 (group 2), 10 (group 3), 20 (group 4), and 30 (group 5) min; untreated tissues (group 1) served as the control. The treated tissues were subdermally implanted into 3-week-old male Wistar rats and kept in place for 28 days. The calcification in each explant was semiquantitatively evaluated by annotating and measuring the area using virtual slides, and the data obtained were statistically analyzed., Results: Semiquantitative analysis revealed that calcification of the implants from the untreated group (group 1; P = 0.0014) and groups 4 (P = 0.0014) and 5 (P = 0.0031) was significantly lower than that of implants from group 2. Moreover, implants from group 3 showed a tendency toward decreased calcification, although it was not significant (P = 0.0503)., Conclusions: A rapid ethanol treatment prevents calcification of GA-fixed tissues in a rat model of subdermal implantation. This method may facilitate effective and rapid anticalcification of autologous tissues for use during cardiovascular surgery., (© 2022. The Author(s).)

Interstitial pneumonia (IP) is a major risk factor for lung adenocarcinoma (LADC). IP-related LADC predominantly develops in the bronchiolar metaplasia lining in honeycomb lesions. Kirsten rat sarcoma virus ( KRAS ) is the most common oncogene mutated in IP-related LADC. The present study examined the metaplastic epithelia in honeycomb lesions for KRAS mutations using digital droplet polymerase chain reaction (ddPCR), a sensitive method used to detect infrequent mutations. Significantly higher KRAS mutation variant allele frequencies (VAFs) were detected in the metaplastic lung epithelia from 13 patients with IP compared with those in 46 non-lesioned lung samples from patients without IP (G12V, P=0.0004, G12C, P=0.0181, and G12A, P=0.0234; Mann Whitney U test). Multivariate analyses revealed that higher KRAS G12V (logistic regression model; P=0.0133, odds ratio=7.11) and G12C (P=0.0191, odds ratio=5.81) VAFs in patients with IP were independent of confounding variables, such as smoking and age. In patients with IP, metaplastic epithelia exhibited significantly higher KRAS G12V and G12C VAFs compared with the non-lesioned counterparts (paired t-test; G12V, P=0.0158, G12C, P=0.0465). These results suggested that IP could increase KRAS mutations and supported the hypothesis that bronchiolar metaplasia could be a precursor for IP-related LADC., Competing Interests: The authors declare that they have no competing interests., (Copyright: © Kataoka et al.)

The present study aimed to elucidate the mechanisms underlying the histogenesis of interstitial pneumonia (IP)-related lung adenocarcinoma (LADC). We focused on the methylation of thyroid transcription factor 1 ( TTF-1 ). The TTF-1 locus was highly methylated in IP-LADCs compared to non-IP-LADCs. Among the IP-LADCs, the non-terminal respiratory unit (TRU) LADCs showed marked hypermethylation in CpG sites in a particular intragenic region. This region was also found to be highly methylated in the IP lungs. The hierarchical dendrogram based on methylation levels divided the IP lungs into three different clusters. One of them showed a methylation profile similar to that of non-TRU LADCs. The non-TRU LADCs developed from this cluster with a significantly higher frequency. Moreover, bronchiolar metaplasia lining honeycomb/cystic lesions in IP lungs, IP-related non-TRU LADCs, and bronchiolar epithelia in healthy lungs were separately collected by microdissection and examined for methylation. Bronchiolar metaplasia showed hypermethylation, but bronchiolar epithelia did not. The methylation patterns in bronchiolar metaplasia were similar to those in non-TRU LADCs. In summary, a particular region of TTF-1 was highly methylated in IP-related non-TRU LADCs and bronchiolar metaplasia, supporting the theory that IP-related non-TRU LADCs may develop from bronchiolar metaplasia lining honeycomb/cystic lesions., Competing Interests: None., (IJCEP Copyright © 2022.)

Background: The usefulness and safety of transbronchial lung cryobiopsy (TBLC) for reassessment of diffuse parenchymal lung disease (DPLD) with progression is still unknown. Our purpose was to clarify the usefulness and safety of TBLC for reassessment of DPLD with progression., Methods: This retrospective study included 31 patients with DPLD diagnosed by surgical lung biopsy who progressed in the clinical course and underwent TBLC for reassessment between January 2017 and September 2019 at Kanagawa Cardiovascular & Respiratory Center. Two pulmonologists independently selected the clinical diagnosis, treatment strategy, and confidence level of the treatment strategy based on clinical and radiological information with and without pathological information from TBLC. A consensus was reached among the pulmonologists regarding the clinical diagnosis, treatment strategy, and confidence level of the treatment strategy. Complications of TBLC were also examined., Results: Seven (22.6%), 5 (16.1%), and 6 (19.4%) of clinical diagnosis was changed after TBLC for Pulmonologist A, for Pulmonologist B, and for consensus, respectively. The treatment strategy was changed in 7 (22.6%), 8 (25.9%), and 6 (19.4%) cases after TBLC for Pulmonologist A, for Pulmonologist B and for consensus, respectively. The definite or high confidence level of the consensus treatment strategy was 54.8% (17/31) without TBLC and 83.9% (26/31) with TBLC. There were 6 cases of moderate bleeding, but no other complications were noted., Conclusions: Pathological information from TBLC may contribute to decision-making in treatment strategies for the progression of DPLD, and it may be safely performed., (© 2022. The Author(s).)

Pneumocyte injury is a crucial factor influencing the severity of interstitial lung disease (ILD). In this study, we investigated the potential of hepatocyte nuclear factor α (HNF4α) as an immunohistochemical marker to detect pneumocyte injury and as a prognostic marker. Surgical lung biopsy specimens were collected from 309 patients with different types of ILDs (61 idiopathic pulmonary fibrosis (IPF), 173 non-IPF, and 75 unclassifiable ILD). HNF4α expression were examined and the frequency of positive cells (per mm 2 ) was calculated. HNF4α was strongly expressed in regenerating pneumocytes present on fibroblastic foci, Masson bodies/organizing alveoli. In the non-IPF and unclassifiable ILD groups, cases with high frequency expression showed significantly poorer outcome. Particularly, in the unclassifiable ILD group, the prognostic impact was more significant (death due to ILD, log-rank test, p < 0.0001), with a 10-year survival rate (hazard ratio 11.1, Wald test, p = 0.0003), as compared to the non-IPF group (log-rank test, p = 0.0269; hazard ratio 2.7, Wald test, p = 0.0334). Multivariable analysis focusing on the unclassifiable ILD group confirmed that the frequent HNF4α expression was an independent prognostic factor (hazard ratio 28.6; Wald test, p = 0.0033). Thus, HNF4α can be utilized as an immunohistochemical marker for pneumocyte injury and have prognostic impact particularly in unclassifiable ILD., (© 2021 Japanese Society of Pathology and John Wiley & Sons Australia, Ltd.)