Involvement of the lung is common in systemic AL amyloidosis in post-mortem series. However, the diagnosis is challenging. Histology is the gold standard but may result in bleeding. Consequently, diagnosis during life is rare.

A 58-year-old female was admitted with chest pain, weight loss and cough. Thorax CT showed diffuse ground glass opacities, increased nodular density, and conglomerated mediastinal lymph nodes. Lung biopsy revealed Congo red (+) and anti-amyloid A (-). Bone marrow showed clonal plasma cell increase as 15% of kappa type. No other organ involvement or lytic lesions on PET-CT were documented. Cardiac involvement was detected. Daratumumab-bortezomib-based treatment with doxycycline was started.

Clinical symptoms and laboratory testing cannot specially confirm the diagnosis of pulmonary amyloidosis.The usual presentation is diffuse-alveolar septal involvement. Diffuse parenchymal involvement is one of the least common forms of respiratory amyloidosis. It should be considered in the differential diagnosis in elderly patients.