A descriptive analysis of 21 patients with pulmonary amyloidosis: An observational study

Pulmonary amyloidosis is an extremely rare disease, often detected incidentally because of its asymptomatic nature and potential to result in fatal outcomes. In this study, we aimed to present the clinical and radiological features of patients diagnosed with pulmonary amyloidosis by biopsy. This descriptive study included 21 patients with pathologically diagnosed pulmonary amyloidosis. Pulmonary amyloidosis was classified as diffuse alveolar-septal amyloidosis (DASA), cystic amyloidosis (CPA), tracheobronchial amyloidosis (TBA), nodular amyloidosis (NPA), and extraparenchymal pulmonary amyloidosis (pleural and mediastinal lymph node). Clinical, bronchoscopic, and radiological specific characteristics were presented in detail to be used for differential diagnosis. The median age of the patients was 63 (40-83) years, and 14 (66.7%) were male. Twenty patients (95.2%) presented with at least 1 comorbidity. All patients diagnosed with tracheobronchial amyloidosis were symptomatic at presentation, whereas those diagnosed with NPA/extraparenchymal amyloidosis were often asymptomatic. The patients included 1 case of DASA, 1 case of CPA, 10 cases of NPA, 6 cases of TBA, and 3 cases of extraparenchymal amyloidosis involving the mediastinal lymph node and pleura. Sixteen patients (76.2%) were classified as localized amyloidosis, while 5 patients (23.8%) were classified as systemic amyloidosis following the diagnosis of multiple myeloma, monoclonal gammopathy of undetermined significance, systemic lupus erythematosus, Sjogren's syndrome, and B-cell lymphoma. Bronchoscopic biopsies were sufficient for diagnosis, and notably, even transbronchial needle aspiration could be a useful diagnostic method. During the follow-up, we observed that the disease remained stable without progression. However, it is important to note that patients with concurrent malignancies experience fatal outcomes. In conclusion, it is crucial to distinguish pulmonary amyloidosis from other pulmonary diseases such as malignancies, infectious diseases, and interstitial lung diseases, which may have similar clinical and radiological findings. Bronchoscopic diagnostic methods are usually sufficient for the diagnosis. Although patients with pulmonary involvement mostly remain stable during long-term follow-up without progression, it is important to consider the risk of malignancy.