Non-resolving Pulmonary Consolidation Mimicking Tuberculosis: A Diagnostic Pitfall Revealing Lung Adenocarcinoma.

Pulmonary tuberculosis (TB) remains highly prevalent in endemic regions; however, current international and national guidelines emphasize microbiological confirmation prior to initiation of anti-tubercular therapy (ATT) whenever feasible. Empirical treatment without microbiological confirmation represents a deviation from recommended standards and may contribute to diagnostic delay. We report a 52-year-old male presenting with chronic cough with mucoid expectoration and progressive dyspnea without fever, hemoptysis, or weight loss. Despite negative sputum acid-fast bacilli (AFB) smear and cartridge-based nucleic acid amplification test (CBNAAT), the patient was empirically initiated on ATT based on clinicoradiological suspicion. Lack of clinical and radiological response prompted further evaluation. High-resolution computed tomography (HRCT) demonstrated persistent consolidation with perilymphatic nodules and interlobular septal thickening. Positron emission tomography-computed tomography (PET-CT) revealed metabolically active pulmonary lesions with mediastinal lymphadenopathy and a suspicious adrenal lesion. CT-guided biopsy confirmed moderately differentiated lung adenocarcinoma. Molecular analysis revealed a KRAS mutation with negative programmed death-ligand 1 (PD-L1) expression. This case underscores the importance of adherence to diagnostic guidelines, early reconsideration of diagnosis in non-resolving consolidation, and the critical role of timely tissue diagnosis in preventing delays in oncological management.