Nodular pulmonary amyloidosis diagnosed by ultrasound-guided percutaneous needle biopsy

Abstract

Pulmonary amyloidosis is characterized by extracellular deposition of fibrous protein called amyloid in the lungs and has three subtypes: nodular, diffuse, and tracheobronchial amyloidosis. Pulmonary nodular amyloidosis can mimic other lung diseases including infectious diseases, metastatic lung tumors, sarcoidosis, and pulmonary hyalinizing granuloma. A biopsy of the lesion is essential for a definitive diagnosis. Herein, we report the case of a 66-year-old man who presented for shortness of breath on exertion and was diagnosed with nodular pulmonary amyloidosis on ultrasound-guided percutaneous needle biopsy. A chest X-ray and computed tomography (CT) revealed bilateral slowly growing multiple calcified pulmonary nodules and cavities. Malignancy was suspected based on 18F-fluoro-deoxyglucose (18F-FDG) positron emission tomography/CT (PET/CT) images. An ultrasound-guided percutaneous needle biopsy was performed, and histopathologic examination of the lesion confirmed nodular pulmonary amyloidosis. This case highlights the importance of considering nodular pulmonary amyloidosis in the differential diagnosis of pulmonary nodules with increased uptake of 18F-FDG on PET/CT and the utility of ultrasound-guided needle biopsy in the definitive diagnosis.

Keywords: 18F-fluoro-deoxyglucose (18F-FDG) positron emission tomography; Nodular pulmonary amyloidosis; Systemic AL amyloidosis; Ultrasound-guided percutaneous needle biopsy.

Fig. 1

Chest CT imaging on admission showed multiple nodules and masses with calcification and cysts in both lungs (A). A CT scan of the chest 10 years earlier (B) already showed the presence of calcified nodules, which were smaller than on the present CT images.

Fig. 2

18F-FDG PET/CT showed varying degrees of FDG uptake in non-calcified areas of several nodes.

Fig. 3

Transthoracic ultrasonography revealed a lesion in contact with the pleura of the left lung (white arrows).

Fig. 4

Histopathological findings of pulmonary nodules collected by US-guided biopsy are shown. Hematoxylin-eosin staining (A) shows abundant amorphous eosinophilic material with focal calcification displacing the lung parenchyma. Congo red staining (B) shows that these amorphous eosinophils are pink or red, suggesting amyloidosis.