Amyloidosis is caused by abnormal protein deposition in various tissues, including the lungs. Pulmonary manifestations of amyloidosis may be categorized by areas of involvement, such as parenchymal, large airway and pleural involvement. We describe four distinct manifestations of amyloidosis involving the lung and review their clinical, radiological and pathological features and summarize the evidence for treatment in each of these presentations. We describe alveolar-septal amyloidosis, cystic amyloid lung disease, endobronchial amyloidosis and pleural amyloidosis.

Amyloidosis is a disease caused by misfolded proteins that deposit in the extracellular matrix as fibrils, resulting in the dysfunction of the involved organ. The lung is a common target of Amyloidosis, but pulmonary amyloidosis is uncommonly diagnosed since it is rarely symptomatic. Diagnosis of pulmonary amyloidosis is usually made in the setting of systemic amyloidosis, however in cases of localized pulmonary disease, surgical or transbronchial tissue biopsy might be indicated. Pulmonary amyloidosis can be present in a variety of discrete entities. Diffuse Alveolar septal amyloidosis is the most common type and is usually associated with systemic AL amyloidosis. Depending on the degree of the interstitial involvement, it may affect alveolar gas exchange and cause respiratory symptoms. Localized pulmonary Amyloidosis can present as Nodular, Cystic or Tracheobronchial Amyloidosis which may cause symptoms of airway obstruction and large airway stenosis. Pleural effusions, mediastinal lymphadenopathy and pulmonary hypertension has also been reported. Treatment of all types of pulmonary amyloidosis depends on the type of precursor protein, organ involvement and distribution of the disease. Most of the cases are asymptomatic and require only close monitoring. Diffuse alveolar septal amyloidosis treatment follows the treatment of underlying systemic amyloidosis. Tracheobronchial amyloidosis is usually treated with bronchoscopic interventions including debulking and stenting or with external beam radiation. Long-term prognosis of pulmonary amyloidosis usually depends on the type of lung involvement and other organ function.

The current case report presents a 59-year-old man with imaging studies of the thorax showing nodular lesions in the lungs bilaterally. Based on radiographic and CT images, preliminary diagnoses for possible granulomatosis (tuberculosis) or pulmonary metastatic dissemination of a neoplastic process were made. An ultrasound-controlled transthoracic true-cut needle biopsy of a subpleural lesion was performed. Special staining with Congo red and examination with a polarizing light microscope for detection of amyloid confirmed the diagnosis of \'pulmonary nodular amyloidosis\' by visualizing green birefringence.

B-cell lymphoproliferative disorders are characterized by the accumulation of mature B lymphocytes in the bone marrow, lymphoid tissues, and/or peripheral blood. They can cause amyloid deposits in the lungs. In rare cases, lung nodules can be the first sign of this disorder. We present the case of an 89-year-old woman with stable shortness of breath and lung nodules on imaging. A positron emission tomography-computed tomography (PET-CT) scan showed the most intense hypermetabolic nodule in the patient\'s lung, which was 1.5 × 1.4 cm. A biopsy of this nodule showed amyloid material with trapped plasma cell infiltrate on microscopy. Congo red stain under polarizing microscopy showed apple-green birefringence, which is diagnostic for amyloidosis. Immunohistochemistry showed a mixture of kappa-positive and lambda-positive cells. B-cell gene rearrangement-clonal gene rearrangements were detected in the immunoglobulin heavy chain (IgH) gene and the kappa light chain (IGK). These findings suggest a B-cell lymphoproliferative disorder, such as a plasmacytoma or a marginal cell lymphoma with plasma cell differentiation. The patient was diagnosed with a B-cell lymphoproliferative disorder and pulmonary amyloidosis. Isolated amyloidosis in the lungs usually has a good prognosis, but it can be a sign of autoimmune diseases or B-cell lymphoproliferative disorders, as in this case. Early diagnosis of B-cell lymphoproliferative disorder can lead to successful treatment and prevents complications.

Pulmonary amyloidosis should be included in the differential diagnosis of calcified lung nodules, and more careful preparation for bleeding should be taken when performing bronchoscopy. While management does not require aggressive treatment, follow-up is necessary to monitor for multiple myeloma and malignant lymphoma.

Amyloidosis is a rare disease that involves the extracellular deposition of abnormally folded proteins, precipitating organ dysfunction. Pulmonary amyloidosis is frequently characterized by the AL amyloid subtype and can be localized or associated with systemic involvement, presenting in a nodular, diffuse alveolar-septal, or tracheobronchial pattern. Presentation of disease can vary from clinically silent to severe. Pulmonary amyloidosis is typically first suspected on CT scan of the chest. Diagnostic workup requires tissue biopsy and identification by immunohistochemical staining. Systemic treatment has evolved over recent years to include the combination of daratumumab, bortezomib, cyclophosphamide, and dexamethasone (dara-VCD) as first-line therapy, with the goal of quickly attaining complete hematologic response. Through clinical vignettes, we review pulmonary AL amyloidosis and discuss current treatment options.

Pulmonary amyloidosis is a rare disease characterized by abnormal extracellular deposition of amyloid fibril in the lung tissue, and the identification of amyloid deposits is essential for its diagnosis. Surgical lung biopsy (SLB) is a standard diagnostic method for pulmonary amyloidosis. However, it has a relatively high post-procedural mortality rate. Recently, transbronchial lung cryobiopsy (TBLC) has been gradually used for diagnosing interstitial lung disease. However, its diagnostic efficacy for pulmonary amyloidosis has not yet been validated. Here, we describe two cases of pulmonary amyloidosis with deposition of amyloid light chain detected via TBLC. Since SLB is a high-risk procedure for the patients due to age and complications, TBLC was performed. Both patients presented with Congo red-positive amyloid deposits. One patient with localized pulmonary amyloidosis had a good clinical course without therapeutic intervention and was followed up. The other with systemic amyloidosis received chemotherapy and presented with a stable clinical course. TBLC can collect a larger pulmonary specimen for pulmonary amyloidosis than forceps biopsy and has fewer complications and a lower mortality rate than SLB. Thus, it can be a diagnostic method for pulmonary amyloidosis.

We present the case of a 58-year-old man who presented with dyspnea, cough, and weight loss and was ultimately diagnosed with pulmonary amyloidosis and multiple myeloma. Diagnosis was achieved with a lung biopsy which showed AL amyloid deposits involving the interstitium, vessels, and airway. He was treated with cyclophosphamide, bortezomib, and dexamethasone but died prior to completing treatment. His case is unique for the amyloid deposition found in all three lung compartments with clear pathophysiologic manifestations of each compartment, and the rapid disease progression that led to respiratory failure and death.

A 60-year-old man with a background of resected clear cell renal cancer and resected colorectal adenocarcinoma presented with a pulmonary mass lesion in the left upper lobe which was avid on 18-F FDG PET/CT. Needle biopsy confirmed metastatic renal cell cancer, which was surgically excised with wedge resection. Follow-up imaging 6 months later demonstrated a second slowly enlarging subcentimeter nodule in the contralateral lung with increasing FDG avidity, suspicious of further small volume oligometastatic disease. Following surgical resection of the second pulmonary lesion, histopathological examination demonstrated nodular pulmonary amyloidosis and no evidence of malignancy.

UNASSIGNED: Pulmonary nodules are a frequent finding on chest imaging studies, with differential including multiple benign entities, but malignancy is often also a concern. Computed Tomography (CT) and Fluorodeoxyglucose (FDG)-Positron Emission Tomography (PET) scans have improved the characterization of pulmonary nodules. However, many nodules remain indeterminate and require periodic monitoring. Here we report two nodular pulmonary amyloidosis cases as a rare etiology of enlarging pulmonary nodules with FDG avidity.
UNASSIGNED: Case 1: 75-year-old woman with a history of asthma, emphysema, bronchiectasis, and a 48 pack-year smoking history was found to have subcentimeter groundglass pulmonary nodules in the right lower lobe (RLL). Follow-up imaging demonstrated an increased solid component of a RLL bulla associated with mild FDG uptake on PET scan. A CT-guided biopsy revealed amyloid deposition. Case 2: 77-year-old man with a history of interstitial lung disease, asbestos exposure, prior tobacco use, and atrial fibrillation treated with amiodarone was found to have a 1.6cm RLL nodule. Follow-up imaging identified an interval increase to 2.0cm associated with moderate FDG uptake on PET scan. Transthoracic biopsy identified amyloid deposition.
UNASSIGNED: Nodular pulmonary amyloidosis is a rare form of amyloidosis which may present as an enlarging pulmonary nodule with FDG avidity, raising concern for malignancy. A CT-guided biopsy is a safe way to establish a diagnosis. Recent studies have demonstrated an association between nodular pulmonary amyloidosis and marginal zone lymphomas, which warrants longitudinal follow-up for evolution to lymphoproliferative disorder.