Lee-Mateus, A Yu

Abstract Introduction The diagnosis of fungal lung infections remains challenging as standard tests, such as bronchoalveolar lavage (BAL) antigen testing, often yield variable or inconclusive results. These limitations can delay appropriate therapy and may require additional tissue sampling for definitive diagnosis. Robotic-assisted bronchoscopy (RAB) biopsy has been primarily used as a minimally invasive technique for assessing suspicious peripheral pulmonary lesions (PPL). This case series highlights the diagnostic utility of RAB for identifying fungal infections within PPL when conventional BAL antigen analysis is non-diagnostic. Case Description Four patients with suspected infectious or malignant PPL underwent RAB-guided biopsy for diagnostic clarification, all yielding histopathologic confirmation of fungal disease. The first, a 73-year-old bilateral lung-transplant recipient with hemoptysis, had a negative BAL Aspergillus antigen despite RAB biopsy confirming Aspergillus infection. Similarly, a second 73-year-old man with chronic obstructive pulmonary disease (COPD) and esophageal adenocarcinoma had a negative BAL antigen, while RAB biopsy of bilateral cavitary lesions confirmed Aspergillus. Additionally, a 39-year-old woman with a nodule being evaluated for malignancy, had negative BAL Histoplasma antigen and PCR, whereas RAB biopsy confirmed Histoplasma capsulatum. In contrast, a 56-year-old woman with a right-lower-lobe nodule had a positive BAL Aspergillus antigen that aligned with the histopathologic biopsy findings. Discussion BAL-based antigen testing demonstrates variable diagnostic accuracy in fungal lung disease. Reported sensitivities for Aspergillus detection are typically high in meta-analysis, approximately 80%-90%, but clinical performance in the immunocompromised or high-risk patients is often substantially lower. Similarly, while BAL antigen testing for Histoplasma performs well in disseminated infections, it often fails to detect localized pulmonary disease. In this series, three out of four patients had negative BAL results in the presence of histopathologic confirmation of fungal infection. While current guidelines consider BAL positivity supportive of a “probable” diagnosis, tissue histopathology remains the gold standard for a “proven” infection. These findings emphasize the value and capability of RAB in obtaining direct tissue confirmation when conventional testing, such as BAL antigen analysis, is non-diagnostic. Conclusion RAB-guided biopsy of PPLs offers the opportunity for histopathologic confirmation of fungal infection when BAL testing is non-diagnostic. This approach can enhance upfront diagnostic yield in patients with suspected fungal pulmonary infections, avoiding delays in diagnosis and treatment initiation. This abstract is funded by: None

Abstract Rationale Advances in bronchoscopic technology, including robotic-assisted bronchoscopy (RaB) and cone-beam CT (CBCT), have enabled biopsy of multiple nodules in a single procedure. Here we present the procedural characteristics, safety, diagnostic yield, and use of linear endobronchial ultrasound (EBUS) staging in patients with multifocal pulmonary nodules biopsied under a single anesthesia event. Methods This multi-center, retrospective observational study included adults undergoing RaB biopsy of multifocal peripheral pulmonary lesions and lymph node assessment under a single anesthesia event at six U.S. centers from 11/2019 - 8/2025. Procedures utilized either the Ion (Intuitive) or Monarch (Ethicon) systems under general anesthesia. De-identified demographic, radiologic, procedural, pathologic, and safety data were collected in a secure centralized database. Safety outcomes included pneumothorax and its sequelae, hypoxia, and infectious complications. Diagnostic yield was determined using the 2024 ATS/ACCP consensus statement. NGS adequacy was reported from two health systems with well-defined criteria for sufficiency and standard institutional practices for sending NGS testing on both nodules. Statistical analyses utilized included descriptive statistics, t-tests, chi-squared/Fisher’s tests where appropriate, and logistic regression. Results Among 191 patients, 177 underwent biopsy of two and 14 of three nodules. Lymph nodes were sampled in 167 (87.4%), with 18 (10.8%) positive for malignancy; notably, 17 of 18 (94%) patients with nodal metastases had at least one fully solid nodule. Complications occurred in 20 patients (10.5%), including pneumothorax in 14 (7.3%), with 4 (2.1%) requiring tube thoracostomy. There were no cases of bilateral pneumothorax. Transient hypoxia occurred in 3 patients (1.6%) and 3 developed outpatient-managed bronchitis. Seven patients (3.7%) required unplanned admission. Overall diagnostic yield was 72.2%, with 122 (63.9%) patients having two diagnostic nodules and 33 (17.4%) having two non-diagnostic nodules. Bronchus sign (OR 2.9, p = 0.003), radial EBUS use (OR 2.6, p = 0.025), and CBCT use (OR 2.4, p = 0.021) were associated with procedures having two diagnostic nodules. At sites with standardized NGS adequacy reporting, 74 of 81 malignant nodules (91%) provided sufficient tissue for NGS. Conclusions •Single-procedure biopsy of multifocal pulmonary nodules is feasible, safe, and achieves industry-standard strict diagnostic yield. •Complications are slightly higher than single-nodule procedures. Serious events were rare. •17 of 18 patients with malignant nodal disease had at least one fully solid nodule; no patients with two pure ground glass nodules had nodal metastasis. •NGS testing was feasible and adequate on the majority of samples, aiding clinicians in staging multifocal nodules. This abstract is funded by: None