Mimicking pulmonary multiple metastatic tumors: A case of primary nodular parenchymal pulmonary amyloidosis with review of the literature

Primary pulmonary amyloidosis is a relatively rare condition, characterized by amyloid deposition in the lungs and other associated structures. We report a case of primary nodular parenchymal pulmonary amyloidosis in a 44-year-old male. The patient was referred to our hospital for further evaluation of multiple lobulated nodules in both lungs. As the multiple lung nodules were suspected to be metastatic, (18)F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) was conducted, which revealed that the nodules had a mild uptake of (18)F-FCG. Amyloidosis was confirmed by conducting a percutaneous CT-guided fine-needle aspiration (FNA) biopsy in the left lung nodule. A literature review of previous studies on primary nodular parenchymal pulmonary amyloidosis from Medline (1970-October 2011) and Embase (1989-October 2011) was also included. Despite its rarity, primary nodular parenchymal pulmonary amyloidosis with a pattern of multiple nodules also forms part of the differential diagnosis of pulmonary metastases with high (18)F-FDG uptake on PET/CT.