[Primary amyloidosis presenting with interstitial lung disease and pleural effusion: a case report].

Primary light-chain amyloidosis is a rare disease, and pulmonary manifestations such as interstitial lung disease and pleural effusion are distinctly uncommon. Here we reported a case presenting with non-specific dyspnea and edema. Imaging showed pulmonary interstitial involvement characterized by diffuse interlobular septal thickening and refractory pleural effusion. The initial misdiagnosis of sarcoidosis and tuberculosis delayed the accurate diagnosis. Ultimately, multi-systems involvement with persistent proteinuria prompted further investigation, which revealed kappa monoclonal protein and led to the definitive diagnosis by tissue biopsy. This report highlights the imperative to consider amyloidosis in patients with unexplained interstitial lung disease and pleural effusion.