CRA50 DOUBLE TROUBLE – RADIAL EBUS-GUIDED DIAGNOSIS OF UNDERLYING LUNG ADENOCARCINOMA MASQUERADING AS INFECTION

Syahrinnaquiah Samsuddin¹, Yen Shen Wong¹, Am Basheeri Alias¹, Mohd Zhafran Zainal¹, Aisya Natasya Musa¹

¹Respiratory Unit, University Teknologi Mara (UITM)

Introduction
Lung malignancies may initially present as pneumonia, often delaying diagnosis due to overlapping clinical and radiographic features. Timely identification is crucial for better outcomes. We report a case of lung adenocarcinoma initially masked by infection, with diagnosis achieved via radial EBUS-guided transbronchial lung biopsy (TBLB).

Case report
A 73-year-old ex-smoker with diabetes, chronic kidney disease, and coronary artery disease presented with a two-week history of fever and cough. Inflammatory markers were raised and chest radiograph showed right middle zone consolidation. Bronchoscopy and lavage cultured Klebsiella pneumoniae, and intravenous amoxicillin-clavulanate was initiated. Despite treatment, repeat CT thorax showed persistent right lower lobe consolidation. Radial EBUS-guided TBLB revealed a concentric lesion, and histopathology confirmed lung adenocarcinoma. Tissue was sent for next-generation sequencing (NGS), and staging workup was planned post-infection resolution. 

Discussion
Pneumonia can mask an underlying lung malignancy. A high index of suspicion is essential when radiological abnormalities persist despite appropriate antibiotic therapy. Literature shows a median delay of up to 297 days in diagnosing malignancy in such cases. Radial EBUS is a valuable tool in evaluating peripheral pulmonary lesions, with a diagnostic yield of approximately 73%. Its success is influenced by lesion characteristics, bronchus sign, guide sheath use, and operator experience.

Conclusion
This case underscores the importance of considering malignancy in non-resolving pneumonia and demonstrates the effectiveness of radial EBUS-guided biopsy in achieving timely and accurate diagnosis.

Keywords: lung malignancy, adenocarcinoma, Klebsiella pneumoniae, radial EBUS, transbronchial biopsy