Localized nodular pulmonary amyloidosis observed on medical examination

A 53-year-old man underwent a medical examination, which revealed an abnormal nodular shadow. A chest computed tomography (CT) showed a nodule in his right lower lobe, and therefore, bronchoscopic examination was performed. The results of this examination did not result in a definitive diagnosis, and therefore, the wait-and-see approach was employed. Five months later, a follow-up CT showed that the size of the nodule had increased. As malignancy could not be ruled out, partial resection of the right lower lobe was performed. Pathological examination revealed that the nodule contained deposits of an eosinophilic structural material and therefore, primary localized nodular pulmonary amyloidosis was diagnosed. Nodular pulmonary amyloidosis lesions, which are relatively rare, can grow and should be differentiated from malignant nodules.