Background. Tracheal diverticulum is a relatively rare disease. We encountered two patients who presented with a chief complaint of bloody sputum that led to the detection of tracheal diverticulum. Cases. Case 1 involved a 78-year-old man who presented our hospital with a chief complaint of bloody sputum associated with a fever. Computed tomography (CT) revealed bronchial dilatation in both lungs and a small cystic lesion on the right posterolateral wall of the trachea. Bronchoscopy showed a depressed lesion with an orifice that opened only during inspiration. Based on these findings, the diagnosis of tracheal diverticulum was made. Case 2 involved a 71-year-old man who presented to our hospital with a chief complaint of mild bloody sputum. CT revealed a cystic lesion on the right posterior wall of the upper trachea. In addition, bronchoscopy revealed outward protrusion of the tracheal wall and a depressed lesion in the membranous portion of the trachea. No apparent fistula was observed. Conclusion. Although tracheal diverticulum may be incidentally detected by CT, fistulae are difficult to detect even by bronchoscopy. Caution should be exercised, as the contents of the diverticulum may cause pneumonia.

Background. Angioedema can progress from edema of the tongue and lips to pharyngeal and laryngeal edema, resulting in life-threatening airway stenosis; therefore, appropriate treatment at the onset is important. Case. A 75-year-old male smoker receiving anticancer drug therapy for prostate cancer underwent endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) to examine the right lower paraventricular lymphadenopathy. No complications occurred within 24 h after the operation; however, angioedema developed after 48 h. The angiotensin-converting enzyme (ACE) inhibitor enalapril and dipeptidyl peptidase-4 (DPP-4) inhibitor linagliptin, which can exacerbate ACE inhibitor-mediated angioedema, were discontinued. Hydrocortisone succinate was infused; however, the patient's angioedema worsened. An emergency tracheostomy was performed. Thereafter, the air conduction stenosis due to edema was improved. Conclusion. We encountered a patient with prostate cancer who developed ACE inhibitor-mediated angioedema that may have been triggered by EBUS-TBNA. Angioedema due to ACE inhibitors rarely occurs; however, invasive procedures, such as EBUS-TBNA, may trigger the development of angioedema to ACE inhibitors if there are risk factors, such as smoking and DPP-4 inhibitor use.

Background. Bronchial stump fistula is a serious complication after lung resection and often difficult to treat. Recently, various bronchoscopic interventions and their effectiveness have been reported. Case. An 85-year-old man developed pyothorax after right upper lobectomy. Bronchoscopy showed a bronchial fistula in the right upper bronchial stump. We attempted endoscopic bronchial occlusion with a polyglycolic acid (PGA) sheet and fibrin glue, but it was ineffective. Later, we retried endoscopic bronchial occlusion with a PGA sheet and fibrin glue using a combination of bronchoscopy and thoracoscopic surgery. While observing the inside of the cavity with a thoracoscope, the sheet was placed in an appropriate position. After that, the air-leakage stopped and the pyothorax improved. Conclusion. Bronchial intervention with a PGA sheet and fibrin glue is a simple and useful treatment, and combining of bronchoscopy and thoracoscopic surgery is considered effective for ensuring the success of this procedure.

Background. Immunoglobulin (Ig) G4-related disease is characterized by the infiltration of IgG4-positive plasma cells into various organs. A pathological diagnosis based on bronchoscopic or surgical biopsy is required for the definitive diagnosis of IgG4-related respiratory disease. Case Presentation. An 82-year-old man with a 15-year history of hypergammaglobulinemia was examined for bilateral pleural effusion that had been unresponsive to diuretics for approximately half a year. IgG and IgG4 levels in the blood and IgG levels in the pleural effusion were elevated, and thoracoscopy was performed under local anesthesia. A pleural biopsy of the dark brown lesion was performed. The biopsy specimen revealed the infiltration of IgG4-positive plasma cells into the tissue, leading to a diagnosis of IgG4-related pleuritis. The patient was thus treated with prednisolone, and the pleural effusion improved. Conclusion. A pleural biopsy via thoracoscopy under local anesthesia is useful for diagnosing of IgG4-related pleuritis and should be considered if the disease is suspected.

Background. In epidermal growth factor receptor (EGFR) mutation-positive lung cancer, the EGFR T790M mutation and small-cell carcinoma transformation are resistance mechanisms following treatment with first- or second-generation EGFR-tyrosine kinase inhibitors (TKIs). However, the combination of an EGFR T790M mutation and small-cell carcinoma transformation in the same case is rare. Case. A 69-year-old woman was diagnosed with EGFR mutation-positive (L858R) lung adenocarcinoma. The patient was treated with afatinib, followed by carboplatin and pemetrexed. However, the size of the tumor in the right upper lobe of the lung increased. A transbronchial biopsy revealed both T790M mutation-positive adenocarcinoma and small-cell carcinoma transformation. A partial response was obtained after the concomitant administration of osimertinib and cytotoxic chemotherapy, such as carboplatin and etoposide. The cancer was controlled for about 8 months. Conclusion. We encountered a case of EGFR-mutated (T790M mutation) lung adenocarcinoma with small-cell carcinoma transformation after treatment with a second-generation EGFR-TKI. In this case, combination therapy with osimertinib and cytotoxic chemotherapy was effective. Further investigations are warranted in other cases.

Background. Extra care should be taken to ensure safe removal of foreign bodies in the airway of patients with airway stenosis. Case. A woman in her 80s who had undergone permanent tracheostomy after thyroid surgery 60 years earlier visited our emergency department because of dislodgement of the metal tracheal cannula into the trachea during self-replacement. Chest computed tomography showed airway stenosis above the tracheostoma site. After discussion with a multidisciplinary team that included specialists from the general emergency, anesthesia, respiratory medicine, and respiratory surgery departments, foreign body removal using a flexible bronchoscope was performed under preparation for extracorporeal membrane oxygenation to prevent asphyxiation. Conclusion. Extra care must be taken when removing foreign bodies from the trachea of patients with airway stenosis. We were able to successfully perform safe removal due to a multidisciplinary discussion of the extraction method with a back-up plan in the event of respiratory failure.

Background. Endobronchial metastasis of thymomas is rare. We herein report what is, to our knowledge, a very rare case of endobronchial metastasis of thymoma resected using flexible bronchoscopy in Japan. Case Presentation. An 83-year-old man underwent extended thymectomy for a thymoma in 2014. In August 2020, bronchoscopy showed a mass-like lesion at the proximal end of the left upper bronchus, but no histological examination was performed. In April 2021, a bronchoscopic biopsy was performed at his previous hospital. Owing to traction of the biopsy forceps, the tumor was dislodged, causing obstruction of the left main bronchus and persistent bleeding and in turn resulting in left atelectasis and hypoxemia. The patient was referred to our hospital for airway intervention. We resected the tumor using electrosurgical snaring with a flexible bronchoscope. After resection, bleeding from the tumor was controlled through argon plasma coagulation. The tumor was diagnosed as a metastatic of thymoma. His oxygenation status improved, and he was transferred back to his previous hospital. Conclusion. We encountered a rare case of endobronchial metastasis of thymoma that was successfully resected using flexible bronchoscopy.