A 63-year-old woman found to have multiple nodules in both lung fields, and the nodules had enlarged after 4 years. Chest computed tomography scans showed multiple cysts and nodules. We performed lung biopsy by video-assisted thoracoscopic surgery. Hematoxylin and eosin sections from the biopsy specimen showed nodular aggregates of dense eosinophilic, extracellular material with infiltration of lymphocytes and plasma cells. The material was negative for Congo red and had intense staining for monoclonal kappa light chains. The apple-green birefringence was lacking on polarization. Electron microscopy showed massive accumulations of highly dense homogeneous materials lacking any filaments, and no amyloid was found. The other organs were not involved. Because of these findings, pulmonary light-chain deposition disease (LCDD) was diagnosed. We believe that such a case of pulmonary LCDD is quite rare, and the case showed interesting radiological findings.