Pulmonary Amyloidosis as a Differential Diagnosis in Interstitial Lung Diseases.

Pulmonary amyloidosis is an uncommon condition that can mimic interstitial lung diseases (ILDs), leading to diagnostic delays. We describe two cases of diffuse alveoloseptal amyloidosis initially misdiagnosed as ILD. The first involved a 47-year-old woman with systemic AL amyloidosis, successfully treated with CyBorD (Cyclophosphamide, Bortezomib, Dexamethasone) and autologous stem cell transplantation. The second case was a 72-year-old man with localized pulmonary amyloidosis, managed empirically with azathioprine and prednisone, showing slow progression but clinical stability. Histological confirmation using Congo red staining and immunohistochemistry was essential for diagnosis, and systemic disease was excluded through a comprehensive workup. These cases highlight the importance of considering pulmonary amyloidosis in the differential diagnosis of ILDs, especially in patients with unexplained interstitial patterns and monoclonal gammopathy. A multidisciplinary approach is crucial to avoid inappropriate treatment and ensure timely management.