A Rare Presentation of Pulmonary Transthyretin Amyloidosis With Persistent Ground-Glass Opacity Diagnosed by Transbronchial Lung Biopsy.

Pulmonary-dominant transthyretin (TTR) amyloidosis is an uncommon condition. Its presentation with persistent ground-glass opacity (GGO) and infiltrates mimics common respiratory diseases, causing diagnostic delays. Here, we report a case of an 80-year-old male patient with a five-year history of GGO refractory to antibiotics and steroids. Endobronchial ultrasound-guided transbronchial lung biopsy confirmed TTR amyloidosis. Investigations revealed subclinical cardiac involvement, supporting systemic amyloid TTR (ATTR) with a pulmonary-dominant phenotype. Treatment with tafamidis was initiated; however, pulmonary lesions remained radiologically stable at two months and at one year of follow-up. Given that tafamidis is expected to stabilize TTR and slow disease progression rather than rapidly regress established deposits, short-term radiologic stability should be interpreted cautiously. This case demonstrates the diagnostic utility of minimally invasive bronchoscopic techniques for unexplained lung opacities and highlights the need for further evidence regarding the clinical course and treatment response of pulmonary manifestations of ATTR.