Endoscopic resection of bronchial mucoepidermoid carcinoma in a young adult man: A case report and review of literature.

BACKGROUND: Primary tracheobronchial mucoepidermoid carcinoma (MEC), derived from salivary mucus glands, is an uncommon neoplasm in adults. At present, surgery is still the preferred treatment for adult bronchial MEC, although it may cause significant trauma and loss of lung function. Here, we report a patient with endobronchial MEC who received the interventional bronchoscopic therapy to remove the neoplasm and no recurrence occurred during follow-up. CASE SUMMARY: A 28-year-old man was admitted to our unit with mild hemoptysis for 3 d. Physical examination did not show any abnormal signs, and the serological indexes were all in the normal range. Chest computed tomography (CT) indicated an intraluminal nodule in the bronchus intermedius with homogeneous density and a well-defined margin. Upon fiberoptic bronchoscopy, an endobronchial pedunculated polypoid was discovered without submucosal involvement. As the neoplasm was confined to the bronchus, interventional bronchoscopy was performed to remove the mass by high-frequency electric knife and laser resection. Tissue was sampled and histopathological examination confirmed the diagnosis of low-grade MEC. As the proliferation index was low, no further treatment was given. During 2 years of follow-up, the patient's condition was good and no relapse was discovered under fluorescence bronchoscopy or CT scan. CONCLUSION: Interventional bronchoscopy can be considered for treatment of low-grade bronchial MEC, with few complications and preserved lung function.

Microwave ablation via a flexible catheter for the treatment of nonsurgical peripheral lung cancer: A pilot study.

BACKGROUND: Endobronchial microwave ablation via flexible catheter offers the potential for local therapy for inoperable peripheral lung cancer. The study aimed to evaluate the feasibility and safety of navigation bronchoscopy-guided water-cooled microwave ablation catheter for nonsurgical peripheral lung cancer. METHODS: This was a prospective single arm pilot study. Patients with early stage or multiple primary peripheral lung cancer who were nonsurgical candidates for surgery were enrolled in the study. Bronchoscopic microwave ablation was performed via a flexible water-cooled microwave ablation antenna under the guidance of navigation bronchoscopy. Radial probe endobronchial ultrasound combined with fluoroscopy was used to confirm the position. Treatment outcomes were evaluated based on follow-up chest CT and positron emission tomography scans. Primary endpoints were technical success and safety. Secondary endpoints were complete ablation rate, 2-year local control rate, and progression-free survival. RESULTS: Thirteen patients were enrolled in the study from April 2018 to July 2019. A total of 19 sessions of microwave ablation were performed on 14 tumors under the guidance of navigation bronchoscopy. The technical success was 100%. Treatment-related complications occurred in two patients. The complete ablation rate was 78.6% (11/14). The 2-year local control rate was 71.4%. Median progression-free survival was 33 months for all patients. CONCLUSIONS: In this pilot study, bronchoscopic microwave ablation appears to be feasible with acceptable occurrence of complication in the treatment of peripheral lung cancer under the guidance of navigation bronchoscopy.

Proposal of selective wedge instillation of pulmonary surfactant for COVID-19 pneumonia based on computational fluid dynamics simulation.

BACKGROUND: The most important target cell of SARS-CoV-2 is Type II pneumocyte which produces and secretes pulmonary surfactant (PS) that prevents alveolar collapse. PS instillation therapy is dramatically effective for infant respiratory distress syndrome but has been clinically ineffective for ARDS. Nowadays, ARDS is regarded as non-cardiogenic pulmonary edema with vascular hyper-permeability regardless of direct relation to PS dysfunction. However, there is a possibility that this ineffectiveness of PS instillation for ARDS is caused by insufficient delivery. Then, we performed PS instillation simulation with realistic human airway models by the use of computational fluid dynamics, and investigated how instilled PS would move in the liquid layer covering the airway wall and reach to alveolar regions. METHODS: Two types of 3D human airway models were prepared: one was from the trachea to the lobular bronchi and the other was from a subsegmental bronchus to respiratory bronchioles. The thickness of the liquid layer covering the airway was assigned as 14 % of the inner radius of the airway segment. The liquid layer was assumed to be replaced by an instilled PS. The flow rate of the instilled PS was assigned a constant value, which was determined by the total amount and instillation time in clinical use. The PS concentration of the liquid layer during instillation was computed by solving the advective-diffusion equation. RESULTS: The driving pressure from the trachea to respiratory bronchioles was calculated at 317 cmH2O, which is about 20 times of a standard value in conventional PS instillation method where the driving pressure was given by difference between inspiratory and end-expiratory pressures of a ventilator. It means that almost all PS does not reach the alveolar regions but moves to and fro within the airway according to the change in ventilator pressure. The driving pressure from subsegmental bronchus was calculated at 273 cm H2O, that is clinically possible by wedge instillation under bronchoscopic observation. CONCLUSIONS: The simulation study has revealed that selective wedge instillation under bronchoscopic observation should be tried for COVID-19 pneumonia before the onset of ARDS. It will be also useful for preventing secondary lung fibrosis.

Bronchoscopic intervention as a main treatment for tracheobronchial adenoid cystic carcinoma.

BACKGROUND: Bronchial adenoid cystic carcinoma (ACC) is a rare disease with low malignancy and indolent progression. Airway obstruction caused by ACC can be resolved by endoscopic procedures. The efficacy of different techniques of bronchoscopic interventions for ACC has not been determined. MATERIAL AND METHODS: From November 2004 to March 2012, ACC patients, mainly treated with different techniques of bronchoscopic interventions in our hospital, were reviewed. RESULTS: The study included 37 ACC patients. Five patients (13.5%) with intra-luminal type underwent bronchoscopic therapies for a median of three times (range 1-6 times). Thirty-two patients (86.5%) with mixed type underwent bronchoscopic interventions for a median of 14 times (range 4-20 times). The dyspnea index was significantly improved after the first endoscopic procedure. The overall five- and ten-year survival rate was 85.9% and 45.9%, respectively, similar to surgery-dominant treatments. CONCLUSIONS: The present study demonstrates that different procedures of bronchoscopic interventions, as main treatments for ACC, are as effective as surgery-dominant treatment. More prospective and multicentric studies are required to confirm these favorable results, which may influence the therapeutic strategy for ACC in the future.