Diffuse parenchymal pulmonary amyloidosis associated with multiple myeloma: a case report and systematic review of the literature

BACKGROUND: Pulmonary is an uncommon site of extramedullary involvement in multiple myeloma (MM). Diffuse parenchymal amyloidosis as pulmonary manifestation of MM is even rarer. We report a rare case of diffuse parenchymal pulmonary amyloidosis associated with MM diagnosed by video-assisted thoracoscopic lung biopsy (VATLB). CASE PRESENTATION: A 58-year-old woman complained of cough and shortness of breath. HRCT disclosed diffuse ground-glass opacifications with interlobular septal thickening in bilateral lungs. A lung-biopsy sample obtained by VATLB revealed Congo Red-positive amorphous eosinophilic deposits in the alveolar septa. Surgical biopsy of abdominal wall skin and subcutaneous fat was also performed, which showed the apple-green birefringence with polarized light on Congo red stain was demonstrated in dermis. The serum immunoelectrophoresis showed monoclonal lambda light chains. A bone marrow biopsy specimen comprised 11.5% plasma cells. She was therefore diagnosed with diffuse parenchymal pulmonary amyloidosis accompanied by MM. The patient was referred to the hematology department for further chemotherapy. CONCLUSIONS: It is important to recognize diffuse parenchymal pulmonary amyloidosis to avoid misdiagnosis.