Occult lung adenocarcinoma was successfully diagnosed using endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) in a patient with rheumatoid arthritis-associated interstitial lung disease (RA-ILD), respiratory failure, and a recent pneumothorax.
The authors highlighted how pneumothorax and underlying interstitial lung abnormalities can complicate the identification of malignancy in patients with RA-ILD. In this case, continued investigation after the pneumothorax had resolved ultimately revealed an underlying lung tumour.
The case involved a 67-year-old man with a history of smoking and well-controlled rheumatoid arthritis who presented with chest tightness and pleuritic chest pain. Respiratory failure was identified on admission, with a PaO₂ of 58.9 mmHg.
Chest CT demonstrated a left-sided pneumothorax alongside interstitial lung disease. The patient underwent closed thoracic drainage, and subsequent chest X-ray confirmed resolution of the pneumothorax.
However, his chest pain persisted despite successful treatment. Further investigation using CT pulmonary angiography subsequently identified a suspicious mass in the left lower lobe, accompanied by adjacent rib destruction and mediastinal lymphadenopathy.
Obtaining a tissue diagnosis presented a significant clinical challenge. The patient’s pre-existing respiratory failure, underlying ILD, and recent pneumothorax raised concerns that percutaneous biopsy could precipitate recurrent pneumothorax.
Following multidisciplinary assessment, clinicians instead selected EBUS-TBNA to sample the enlarged mediastinal lymph nodes.
EBUS assessment of lymph node stations 7 and 11L successfully provided diagnostic tissue, confirming poorly differentiated lung adenocarcinoma.
The patient subsequently received first-line treatment with pemetrexed, cisplatin, and bevacizumab, after which his condition gradually stabilised.
The case demonstrates how pneumothorax and ILD may obscure an underlying malignancy and potentially delay diagnosis. The authors emphasised that persistent or otherwise unexplained symptoms should prompt further investigation even after an apparent acute cause, such as pneumothorax, has been successfully treated.
The findings also suggest that EBUS-TBNA may provide a useful diagnostic option when suspected lung cancer is accompanied by accessible mediastinal lymphadenopathy and conventional biopsy presents an unacceptable procedural risk.
While evidence from a single case cannot establish the comparative safety or effectiveness of different biopsy approaches, the report illustrates how EBUS-TBNA can facilitate tissue diagnosis in a particularly high-risk clinical setting.
Reference
Zhu C et al. Occult lung adenocarcinoma diagnosed by EBUS-TBNA after pneumothorax resolution in an RA-ILD patient with respiratory failure. BMC Pulm Med. 2026;DOI: 10.1186/s12890-026-04484-9.
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