Problems in the Pathologic Diagnosis of Suspected Lung Cancer / 결핵및호흡기질환

Since the introduction of low-dose computed tomography (CT) screening for patients at high risk of lung cancer, the detection rate of suspicious lung cancer has increased. In addition, there have been many advances in therapeutics targeting oncogenic drivers in non-small cell lung cancer. Therefore, accurate pathological diagnosis of lung cancer, including molecular diagnosis, is increasingly important. This review examines the problems in the pathological diagnosis of suspected lung cancer. For successful pathological diagnosis of lung cancer, clinicians should determine the appropriate modality of the diagnostic procedure, considering individual patient characteristics, CT findings, and the possibility of complications. Furthermore, clinicians should make efforts to obtain a sufficient amount of tissue sample using non- or less-invasive procedures for pathological diagnosis and biomarker analysis.

The diagnosis of peripheral lung lesions: transbronchial biopsy using a radial probe endobronchial ultrasound

Radial probe endobronchial ultrasound (RP-EBUS) has been used in the diagnosis of peripheral lung lesions (PLLs). We reviewed the traditional modality of transbronchial biopsy using RP-EBUS as well as recent developments in improving the diagnostic yield.Current Concepts: Until now, the forceps biopsy of PLLs has played a key role in acquiring tissue samples during the RP-EBUS procedures. Forceps biopsy is a safe and minimally invasive procedure; however, its diagnostic yield was reported to be around 70%, which is significantly lower than that of percutaneous needle aspiration or biopsy. So far, various studies have been conducted to improve the diagnostic yield of the RP-EBUS procedure. The combination of novel navigation systems, such as virtual or electromagnetic navigation bronchoscopies, for locating PLLs in the complex bronchial tree has increased the diagnostic yield of the RP-EBUS procedure. Moreover, newly developed ancillary devices, such as the PeriView FLEX needle or cryobiopsy, as well as traditional modalities such as the guide sheath and brushing cytology, can improve the outcomes of the RP-EBUS procedures. Concerning the bronchoscope size, it has been confirmed that a 3 mm-diameter ultrathin bronchoscope has a higher diagnostic yield than a 4 mm-diameter thin bronchoscope.Discussion and Conclusion: RP-EBUS is a safe and useful method to diagnose PLLs. When traditional and novel modalities are appropriately combined, the diagnostic yield can be increased.

The Additive Impact of Transbronchial Cryobiopsy Using a 1.1-mm Diameter Cryoprobe on Conventional Biopsy for Peripheral Lung Nodules / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#The diagnostic yield of transbronchial biopsy (TBB) using radial probe endobronchial ultrasound (RP-EBUS) is 71%, which is lower than that of transthoracic needle biopsy. We investigated the performance and safety of sequential transbronchial cryobiopsy (TBC) using a novel 1.1-mm diameter cryoprobe, after conventional TBB using RP-EBUS for the diagnosis of peripheral lung lesions (PLLs). @*Materials and Methods@#From April 2021 to November 2021, 110 patients who underwent bronchoscopy using RP-EBUS for the diagnosis of PLL ≤ 30 mm were retrospectively included in our study. All records were followed until June 2022. @*Results@#The overall diagnostic yield of combined TBB and TBC was 79.1%, which was higher than 60.9% of TBB alone (p=0.005). The diagnostic yield of sequential TBC was 65.5%, which increased the overall diagnostic yield by 18.2%. The surface area of tissues by TBC (mean area, 18.5 mm2) was significantly larger than those of TBB by 1.5-mm forceps (3.4 mm2, p < 0.001) and 1.9-mm forceps (3.7 mm2, p=0.011). In the multivariate analysis, PLLs with the longest diameter of ≤ 22 mm were found to be related to additional diagnostic benefits from sequential TBC (odds ratio, 3.51; 95% confidence interval, 1.043 to 11.775; p=0.042). Complications were found in 10.5% of the patients: pneumothorax (1.0%), infection (1.0%), and significant bleeding (8.6%). None of the patients developed any life-threatening complications. @*Conclusion@#Sequential TBC with a 1.1-mm cryoprobe improved the performance of conventional TBB using RP-EBUS without serious complications.

Should We Perform Repeated Re-biopsy for the Detection of T790M Mutation? / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#Epidermal growth factor receptor (EGFR) T790M mutations have been detected in the second or third rebiopsy, even if the T790M mutation was not identified in the first rebiopsy. This meta-analysis investigated the EGFR T790M mutation detection rates and its additional advantages with repeated rebiopsies. @*Materials and Methods@#We searched through the PubMed and EMBASE databases up to June 2022. Studies reporting rebiopsy to identify the EGFR T790M mutation in case of disease progression among patients with advanced non-small cell lung cancer and multiple rebiopsies were included. The quality of the included studies was checked using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. @*Results@#Eight studies meeting the eligibility criteria, reporting 1,031 EGFR mutation–positive patients were selected. The pooled EGFR T790M mutation detection rate of the first and repeated rebiopsies were 0.442 (95% confidence interval [CI], 0.411 to 0.473; I2=84%; p < 0.01) and 0.465 (95% CI, 0.400 to 0.530; I2=69%; p < 0.01), respectively. Overall, the pooled detection rate of EGFR T790M mutation was 0.545 (95% CI, 0.513 to 0.576), which increased by 10.3% with repeated rebiopsies. @*Conclusion@#This meta-analysis identified that repeated rebiopsy increases the detection rate of EGFR T790M mutation by 10.3%, even if EGFR T790M mutation is not detected in the first rebiopsy. Our results indicate that the spatiotemporal T790M heterogeneity can be overcome with repeated rebiopsy.

Association between Participation in a Rehabilitation Program and 1-Year Survival in Patients Requiring Prolonged Mechanical Ventilation / 결핵및호흡기질환

Background@#The present study evaluated the association between participation in a rehabilitation program during a hospital stay and 1-year survival of patients requiring at least 21 days of mechanical ventilation (prolonged mechanical ventilation [PMV]) with various respiratory diseases as their main diagnoses that led to mechanical ventilation. @*Methods@#Retrospective data of 105 patients (71.4% male, mean age 70.1±11.3 years) who received PMV in the past 5 years were analyzed. Rehabilitation included physiotherapy, physical rehabilitation, and dysphagia treatment program that was individually provided by physiatrists. @*Results@#The main diagnosis leading to mechanical ventilation was pneumonia (n=101, 96.2%) and the 1-year survival rate was 33.3% (n=35). One-year survivors had lower Acute Physiology and Chronic Health Evaluation (APACHE) II score (20.2±5.8 vs. 24.2±7.5, p=0.006) and Sequential Organ Failure Assessment score (6.7±5.6 vs. 8.5±2.7, p=0.001) on the day of intubation than non-survivors. More survivors participated in a rehabilitation program during their hospital stays (88.6% vs. 57.1%, p=0.001). The rehabilitation program was an independent factor for 1-year survival based on the Cox proportional hazard model (hazard ratio, 3.513; 95% confidence interval, 1.785 to 6.930; p<0.001) in patients with APACHE II scores ≤23 (a cutoff value based on Youden’s index). @*Conclusion@#Our study showed that participation in a rehabilitation program during hospital stay was associated with an improvement of 1-year survival of PMV patients who had less severe illness on the day of intubation.

Real-world evaluation of atezolizumab and etoposide-carboplatin as a first-line treatment for extensive-stage small cell lung cancer

Background/Aims@#Despite the obvious benefits of adding immune checkpoint inhibitors to platinum-etoposide chemotherapy in patients with extensive-stage small-cell lung cancer (ES-SCLC), real-world data remain scarce. @*Methods@#This retrospective study included 89 patients with ES-SCLC treated with platinum-etoposide chemotherapy alone (chemo-only group; n = 48) or in combination with atezolizumab (atezolizumab group; n = 41) and compared the survival outcomes between these two groups. @*Results@#Overall survival (OS) was significantly longer in the atezolizumab group than in the chemo-only group (15.2 months vs. 8.5 months; p = 0.047), whereas the median progression-free survival was almost the same (5.1 months vs. 5.0 months) in both groups (p = 0.754). Subsequent multivariate analysis revealed that thoracic radiation (hazard ratio [HR], 0.223; 95% confidence interval [CI], 0.092–0.537; p = 0.001) and atezolizumab administration (HR, 0.350; 95% CI, 0.184–0.668; p = 0.001) were favorable prognostic factors for OS. In the thoracic radiation subgroup, patients who received atezolizumab demonstrated favorable survival outcomes and no grade 3–4 adverse events (AEs). @*Conclusions@#The addition of atezolizumab to platinum-etoposide resulted in favorable outcomes in this real-world study. Thoracic radiation was associated with improved OS and acceptable AE risk in combination with immunotherapy in patients with ES-SCLC.

Trends and an Online Survey on the Use of Rigid Bronchoscopy in Korea

Background@#Although almost all interventional pulmonologists agree that rigid bronchoscopy is irreplaceable in the field of interventional pulmonology, less is known about the types of diseases that the procedure is used for and what difficulties the operators face during the procedure. The purpose of this study is to evaluate what diseases rigid bronchoscopy is used for, whether it is widely used, and what challenges the operators face in Korea. @*Methods@#We enrolled 14 hospitals in this retrospective cohort of patients who underwent rigid bronchoscopy between 2003 and 2020. An online survey was conducted with 14 operators to investigate the difficulties associated with the procedure. @*Results@#While the number of new patients at Samsung Medical Center (SMC) increased from 189 in 2003–2005 to 468 in 2018–2020, that of other institutions increased from 0 to 238.The proportion of SMC patients in the total started at 100% and steadily decreased to 59.2%.The proportion of malignancy as the indication for the procedure steadily increased from 29.1% to 43.0%, whereas post-tuberculous stenosis (25.4% to 12.9%) and post-intubation stenosis (19.0% to 10.9%) steadily decreased (all P for trends < 0.001). In the online survey, half of the respondents stated that over the past year they performed less than one procedure per month. The fewer the procedures performed within the last year, the more likely collaboration with other departments was viewed as a recent obstacle (Spearman correlation coefficient, r s = −0.740, P = 0.003) and recent administrative difficulties were encountered (r s = −0.616, P = 0.019). @*Conclusion@#This study demonstrated that the number of patients undergoing rigid bronchoscopy has been increasing, especially among cancer patients. For this procedure to be used more widely, it will be important for beginners to systematically learn about the procedure itself as well as to achieve multidisciplinary consultation.

Treatment Outcomes of Patients with Multidrug-Resistant Tuberculosis: Comparison of Pre- and Post-Public–Private Mix Periods / 결핵및호흡기질환

Background@#This study compared the treatment outcomes of patients with multidrug-resistant tuberculosis (MDR-TB) before and after the implementation of public–private mix (PPM). Factors affecting treatment success were also investigated. @*Methods@#Data from culture-confirmed pulmonary MDR-TB patients who commenced MDR-TB treatment at Pusan National University Hospital between January 2003 and December 2017 were retrospectively reviewed. Patients were divided into two groups in terms of PPM status: pre-PPM period, patients who commenced MDR-TB treatment between 2003 and 2010; and post-PPM period, patients treated between 2011 and 2017. @*Results@#A total of 176 patients were included (64 and 112 in the pre- and post-PPM periods, respectively). 36.9% of the patients were resistant to a fluoroquinolone or a second-line injectable drug, or both. The overall treatment success rate was 72.7%. The success rate of post-PPM patients was higher than that of pre-PPM patients (79.5% vs. 60.9%, p=0.008). Also, loss to follow-up was lower in the post-PPM period (5.4% vs. 15.6%, p=0.023). In multivariate regression analysis, age ≥65 years, body mass index ≤18.5 kg/m2, previous TB treatment, bilateral lung involvement, and extensively drug-resistant (XDR)- or pre-XDR-TB were associated with poorer treatment outcomes. However, the use of bedaquiline or delamanid for ≥1 month increased the treatment success. @*Conclusion@#The treatment success rate in MDR-TB patients was higher in the post-PPM period than in the pre-PPM period, particularly because of the low rate of loss to follow-up. To ensure comprehensive patient-centered PPM in South Korea, investment and other support must be adequate.

Inflammatory Endobronchial Myofibroblastic Tumor: A Case Report

Inflammatory myofibroblastic tumor is a rare benign lesion that accounts for 0.04–1% of all lung tumors and usually appears as a solitary pulmonary nodule or mass. Here, we report the case of an endobronchial inflammatory myofibroblastic tumor in a 21-year-old man with a focus on the imaging findings and a review of previous literature.

A Rare Case of Tracheal Leiomyoma: Role of Digital Tomosynthesis in Diagnosis and Treatment

Tracheal leiomyoma is a rare benign tumor, which is composed of transformed cells of mesenchymal origin. We describe a case in which digital tomosynthesis was useful to evaluate a tracheal tumor that was overlooked on initial chest radiographs.

Risk factors for primary lung cancer among never-smoking women in South Korea: a retrospective nationwide population-based cohort study

Background/Aims@#We performed a large-scale, retrospective, nationwide, cohort study to investigate the risk factors for lung cancer among never-smoking Korean females. @*Methods@#The study data were collected from a general health examination and questionnaire survey of eligible populations conducted between January 1, 2003 and December 31, 2004; the data were acquired from the tailored big data distribution service of the National Health Insurance Service. After a 1-year clearance period, 5,860,922 of 6,318,878 never-smoking female participants with no previous history of lung cancer were investigated. After a median follow-up of 11.4 years, 43,473 (0.74%) participants were defined as “newly diagnosed lung cancer”. @*Results@#After adjusting for all variables at baseline, the variables older age, lower body mass index (BMI), less exercise, frequent alcohol drinking, meat-based diet, rural residence, and previous history of cancer were associated with a higher incidence of lung cancer. Low BMI (< 18.5 kg/m2: hazard ratio [HR], 1.33; 95% confidence interval [CI], 1.27 to 1.40) was a significant independent risk factor; as BMI decreased, HR increased. Negative associations between BMI and lung-cancer development were also observed after controlling for age (p for trend < 0.001). Drinking alcohol one to two times a week (HR, 1.25; 95% CI, 1.21 to 1.28) and eating a meat-based diet (HR, 1.08; 95% CI, 1.01 to 1.15) were associated with lung-cancer incidence. @*Conclusions@#Modifiable baseline characteristics, such as BMI, exercise, alcohol consumption, and diet, are risk factors for lung-cancer development among never- smoking females. Thus, lifestyle modifications may help prevent lung cancer.

Clinical efficacy of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry in patients with multidrug-resistant bacteremia: a single-center study in Korea

BACKGROUND/AIMS@#Matrix-assisted laser desorption/ionization time-of-f light mass spectrometry (MALDI-TOF MS) is a new diagnostic tool for microorganism identification. The clinical usefulness of this approach has not been widely examined in Korea. This retrospective pre–post-intervention quasi-experimental study examined the effect of MALDI-TOF MS on patients with multidrug-resistant (MDR) bacteremia in the intensive care unit (ICU).@*METHODS@#All consecutive patients with MDR bacteremia in the ICU of a tertiary care hospital between March 2011 and February 2013 and between March 2014 and February 2016 were enrolled. MALDI-TOF MS was introduced between these periods. In the pre-intervention and intervention groups, microorganisms were identified by conventional means and by MALDI-TOF MS, respectively. The groups were compared in terms of time from venipuncture to microorganism identification and antimicrobial susceptibility test results.@*RESULTS@#In total, 187 patients (mean age, 61.0 years; 56.7% male) were enrolled. Of these, 97 and 90 were in the pre-intervention and intervention groups, respectively. The intervention group had a significantly shorter time from venipuncture to microorganism identification and antimicrobial susceptibility test results (82.5 ± 21.6 hours vs. 92.3 ± 40.4 hours, p = 0.038). The antibiotics were adjusted in 52 patients (26 each in the pre-intervention and intervention groups) based on these results. These groups did not differ in terms of time from venipuncture to antibiotic adjustment, and multivariate regression analysis showed that MALDI-TOF MS–based microorganism identification was not associated with 28-day mortality.@*CONCLUSIONS@#Our study showed that MALDI-TOF MS accelerated microorganism identification in patients with MDR bacteremia, but did not inf luence 28-day mortality.

Predicting Mortality in Patients with Tuberculous Destroyed Lung Receiving Mechanical Ventilation / 결핵및호흡기질환

BACKGROUND: Patients with acute respiratory failure secondary to tuberculous destroyed lung (TDL) have a poor prognosis. The aim of the present retrospective study was to develop a mortality prediction model for TDL patients who require mechanical ventilation. METHODS: Data from consecutive TDL patients who had received mechanical ventilation at a single university-affiliated tertiary care hospital in Korea were reviewed. Binary logistic regression was used to identify factors predicting intensive care unit (ICU) mortality. A TDL on mechanical Ventilation (TDL-Vent) score was calculated by assigning points to variables according to β coefficient values. RESULTS: Data from 125 patients were reviewed. A total of 36 patients (29%) died during ICU admission. On the basis of multivariate analysis, the following factors were included in the TDL-Vent score: age ≥65 years, vasopressor use, and arterial partial pressure of oxygen/fraction of inspired oxygen ratio <180. In a second regression model, a modified score was then calculated by adding brain natriuretic peptide. For TDL-Vent scores 0 to 3, the 60-day mortality rates were 11%, 27%, 30%, and 77%, respectively (p<0.001). For modified TDL-Vent scores 0 to ≥3, the 60-day mortality rates were 0%, 21%, 33%, and 57%, respectively (p=0.001). For both the TDL-Vent score and the modified TDL-Vent score, the areas under the receiver operating characteristic curve were larger than that of other illness severity scores. CONCLUSION: The TDL-Vent model identifies TDL patients on mechanical ventilation with a high risk of mortality. Prospective validation studies in larger cohorts are now warranted.

The Prognostic Value of the Charlson's Comorbidity Index in Patients with Prolonged Acute Mechanical Ventilation: A Single Center Experience / 결핵및호흡기질환

BACKGROUND: The aim of our study was to evaluate the prognostic value of Charlson's weighted index of comorbidities (WIC) in patients with prolonged acute mechanical ventilation (PAMV, ventilator care ≥96 hours). METHODS: We retrospectively enrolled 299 Korean PAMV patients who were admitted in a medical intensive care unit (ICU) of a university-affiliated tertiary care hospital between 2008 and 2013. Survivors were defined as patients who survived for 60 days after ICU admission. RESULTS: The patients' mean age was 65.1±14.1 years and 70.6% were male. The mean ICU and hospital length of stay was 21.9±19.7 and 39.4±39.1 days, respectively. In addition, the 60-day mortality rate after ICU admission was 35.5%. The mean WIC was 2.3±1.8, with significant differences between nonsurvivors and survivors (2.7±2.1 vs. 2.1±1.7, p<0.05). The area under the curve of receiver-operating-characteristics curve for WIC was 0.593 (95% confidence interval [CI], 0.523–0.661; p<0.05). Based on Kaplan-Meier curves of 60-day survival, WIC ≥5 had statistically lower survival than WIC <5 (log-rank test, p<0.05). In a multivariate Cox proportional hazard model, WIC ≥5 was associated with poor prognosis (hazard ratio, 1.901; 95% CI, 1.140–3.171; p<0.05). The mortality rate of patients with WIC ≥5 was 54.2%. CONCLUSION: Our study showed a WIC score ≥5 might be helpful in predicting 60-day mortality in PAMV patients.

Chronic obstructive pulmonary disease severity is associated with severe pneumonia

Chronic obstructive pulmonary disease [COPD] is a heterogeneous disorder, and various aspects of COPD may be associated with the severity of pneumonia in such patients. We examined the risk factors associated with severe pneumonia in a COPD population. We performed a retrospective observational study using a prospectively collected database of pneumonia patients who were admitted to our hospital through emergency department between 2008 and 2012. Patients with hospital-acquired pneumonia and those with an immunocompromised status were excluded. Of 148 pneumonia patients with COPD for whom chest computed tomography [CT] scans were available, 106 [71.6%] and 42 [28.4%] were classified as non-severe and severe pneumonia, respectively. Multivariate logistic regression analysis revealed that the severity of airflow limitation [odds ratio [OR], 2.751; 95% confidence interval [CI], 1.074-7.050; P= 0.035] and the presence of emphysema on a chest CT scan [OR, 3.366; 95% CI, 1.104-10.265; P= 0.033] were independently associated with severe pneumonia in patients with COPD. The severity of COPD including the airflow limitation grade and the presence of pulmonary emphysema were independently associated with the development of severe pneumonia

The Natural Course of Endobronchial Inflammatory Polyps as a Complication after Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration / 결핵및호흡기질환

We presented a case of unusual endobronchial inflammatory polyps as a complication following endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) in a patient with tuberculous lymphadenitis. EBUS-TBNA of the right hilar lymph node was performed in a 29-year-old, previously healthy man. The patient was confirmed with tuberculous lymphadenitis and received antituberculosis medication over the course of 6 months. Chest computed tomography, after 6 months of antituberculosis therapy following the EBUS-TBNA showed nodular bronchial wall thickening of the right main bronchus. Histological and microbiological examinations revealed inflammatory polyps. After 7 months, the inflammatory polyps regressed almost completely without need for removal.

Predictors of Recurrence after Curative Resection in Patients with Early-Stage Non-Small Cell Lung Cancer / 결핵및호흡기질환

BACKGROUND: There have been various results from studies concerning the predictors of recurrence in early-stage nonsmall cell lung cancer (NSCLC). Therefore, an accurate assessment is needed to guide effective adjuvant therapy. We investigated the predictors of a recurrence in patients with resected, early-stage NSCLC and the risk factors associated with locoregional or distant recurrence. METHODS: This retrospective study was conducted on patients at the Pusan National University Hospital from January 2006 to December 2011. Patients with pathological stages I or II were included in this study, as based on the seventh edition TNM staging system. Multivariate Cox proportional hazard models were used to identify factors associated with recurrence. RESULTS: Two hundred and forty-nine patients were included. Among them, 180 patients were stage I, and 69 were stage II. Overall, by multivariate analysis, the independent factors associated with a 5-year total recurrence were the presence of visceral pleural invasion (VPI) (p=0.018) and maximal standardized uptake values (SUVs) of tumors on positron emission tomography (PET) >4.5 (p=0.037). The VPI was the only independent risk factor associated with both locoregional and distant recurrence, in the analysis of the patterns of tumor recurrence and their risk factors. In the subgroup analysis of stage I patients, three variables (male, VPI and resection margin positive) were significantly associated with a 5-year recurrence. CONCLUSION: The independent factors associated with postoperative recurrence in early-stage NSCLC were as follows: PET SUV >4.5 and the presence of VPI. For patients with those factors adjuvant therapy should be recommended as a more efficacious treatment.

Silicone Stent Placement for Primary Tracheal Amyloidosis Accompanied by Cartilage Destruction / 결핵및호흡기질환

Primary tracheal amyloidosis (PTA) can lead to airway obstructions, and patients with severe PTA should undergo bronchoscopic interventions in order to maintain airway patency. Focal airway involvements with amyloidosis can only be treated with mechanical dilatation. However, the PTA with diffused airway involvements and concomitant cartilage destructions requires stent placement. Limited information regarding the usefulness of silicone stents in patients with PTA has been released. Therefore, we report a case of diffused PTA with tracheomalacia causing severe cartilage destruction, which is being successfully managed with bronchoscopic interventions and silicone stent placements.

A Case of Pleural Paragonimiasis Confused with Tuberculous Pleurisy / 결핵및호흡기질환

Here, we report a case of pleural paragonimiasis that was confused with tuberculous pleurisy. A 38-year-old man complained of a mild febrile sensation and pleuritic chest pain. Radiologic findings showed right pleural effusion with pleural thickening and subpleural consolidation. Adenosine deaminase (ADA) activity in the pleural effusion was elevated (85.3 IU/L), whereas other examinations for tuberculosis were negative. At this time, the patient started empirical anti-tuberculous treatment. Despite 2 months of treatment, the pleural effusion persisted, and video-assisted thoracoscopic surgery was performed. Finally, the patient was diagnosed with pleural paragonimiasis based on the pathologic findings of chronic granulomatous inflammation containing Paragonimus eggs. This case suggested that pleural paragonimiasis should be considered when pleural effusion and elevated ADA levels are observed.

New-Onset Malignant Pleural Effusion after Abscess Formation of a Subcarinal Lymph Node Associated with Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration / 결핵및호흡기질환

We present a case of an unusual infectious complication of a ruptured mediastinal abscess after endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), which led to malignant pleural effusion in a patient with stage IIIA non-small-cell lung cancer. EBUS-TBNA was performed in a 48-year-old previously healthy male, and a mediastinal abscess developed at 4 days post-procedure. Video-assisted thoracoscopic surgery was performed for debridement and drainage, and the intraoperative findings revealed a large volume pleural effusion that was not detected on the initial radiographic evaluation. Malignant cells were unexpectedly detected in the aspirated pleural fluid, which was possibly due to increased pleural permeability and transport of malignant cells originating in a ruptured subcarinal lymph node from the mediastinum to the pleural space. Hence, the patient was confirmed to have squamous cell lung carcinoma with malignant pleural effusion and his TNM staging was changed from stage IIIA to IV.