Respiratory Tract Amyloidosis. State-of-the-Art Review with a Focus on Pulmonary Involvement

Pulmonary manifestations of amyloidosis

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.

Tracheobronchial Amyloidosis Accompanied with Asthma: A Case Report and a Mini-Review

Tracheobronchial amyloidosis is a rare disease characterized by amyloid deposits on the tracheal and bronchial tissue. Patients with tracheobronchial amyloidosis are asymptomatic or exhibit symptoms, such as chronic wheezing, dyspnea, and cough, that are common manifestations of other disorders, including asthma. A bronchoscopic tissue biopsy using Congo red staining is the key standard for diagnosing tracheobronchial amyloidosis. Treatment strategies vary depending on the degree of airway obstruction. If the obstruction is significant and the patient is symptomatic, repeated bronchoscopic treatment, including local resection, laser therapy, stent placement, and radiation therapy, is considered a safer and better option. It is often misdiagnosed as asthma, but cases of tracheobronchial amyloidosis accompanied with asthma have not been reported. We report a case of intermittent wheezing, cough for 33 years, and shortness of breath on exertion for 7 years, which had aggravated in the previous 22 days. A pulmonary examination revealed diffuse wheezing. Pulmonary function testing revealed an obstructive ventilation dysfunction. Computerized tomography (CT) imaging revealed circumferential and irregular thickening of the tracheobronchial wall tissue with calcification and atelectasis of the right middle and lower lobe of the lung. Bronchoscopy revealed diffuse thickening of the mucosa of the trachea and bilateral main bronchi, with multiple nodular protuberances and relatively narrow lumens. The bronchial biopsies revealed massive amyloid deposits under the bronchial mucosa. The deposits exhibited a green birefringence under crossed polarized light after Congo red positive staining. The patient received standard treatment for asthma, and remains in good general condition without wheezing. It is not difficult to distinguish tracheobronchial amyloidosis through chest CT examination for patients with wheezing as long as this disease was considered. It was interesting that we present a rarer case of patient with tracheobronchial amyloidosis accompanied with asthma which both can cause symptoms such as wheezing.

Stepwise diagnostic algorithm for high-attenuation pulmonary abnormalities on CT

High-attenuation pulmonary abnormalities are commonly seen on CT. These findings are increasingly encountered with the growing number of CT examinations and the wide availability of thin-slice images. The abnormalities include benign lesions, such as infectious granulomatous diseases and metabolic diseases, and malignant tumors, such as lung cancers and metastatic tumors. Due to the wide spectrum of diseases, the proper diagnosis of high-attenuation abnormalities can be challenging. The assessment of these abnormal findings requires scrutiny, and the treatment is imperative. Our proposed stepwise diagnostic algorithm consists of five steps. Step 1: Establish the presence or absence of metallic artifacts. Step 2: Identify associated nodular or mass-like soft tissue components. Step 3: Establish the presence of solitary or multiple lesions if identified in Step 2. Step 4: Ascertain the predominant distribution in the upper or lower lungs if not identified in Step 2. Step 5: Identify the morphological pattern, such as linear, consolidation, nodular, or micronodular if not identified in Step 4. These five steps to diagnosing high-attenuation abnormalities subdivide the lesions into nine categories. This stepwise radiologic diagnostic approach could help to narrow the differential diagnosis for various pulmonary high-attenuation abnormalities and to achieve a precise diagnosis.Critical relevance statement Our proposed stepwise diagnostic algorithm for high-attenuation pulmonary abnormalities may help to recognize a variety of those high-attenuation findings, to determine whether the associated diseases require further investigation, and to guide appropriate patient management. Key points • To provide a stepwise diagnostic approach to high-attenuation pulmonary abnormalities.• To familiarize radiologists with the varying cause of high-attenuation pulmonary abnormalities.• To recognize which high-attenuation abnormalities require scrutiny and prompt treatment.

Pulmonary amyloidosis diagnosed via transbronchial lung cryobiopsy without surgical lung biopsy: A case series

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.

Amyloidosis: Multisystem Spectrum of Disease with Pathologic Correlation

Amyloidosis is a group of conditions defined by extracellular deposition of insoluble proteins that can lead to multiorgan dysfunction and failure. The systemic form of the disease is often associated with a plasma cell dyscrasia but may also occur in the setting of chronic inflammation, long-term dialysis, malignancy, or multiple hereditary conditions. Localized forms of the disease most often involve the skin, tracheobronchial tree, and urinary tract and typically require tissue sampling for diagnosis, as they may mimic many conditions including malignancy at imaging alone. Advancements in MRI and nuclear medicine have provided greater specificity for the diagnosis of amyloidosis involving the central nervous system and heart, potentially obviating the need for biopsy of the affected organ in certain circumstances. Specifically, a combination of characteristic findings at noninvasive cardiac MRI and skeletal scintigraphy in patients without an underlying plasma cell dyscrasia is diagnostic for cardiac transthyretin amyloidosis. Histologically, the presence of amyloid is denoted by staining with Congo red and a characteristic apple green birefringence under polarized light microscopy. The imaging features of amyloid vary across each organ system but share some common patterns, such as soft-tissue infiltration and calcification, that may suggest the diagnosis in the appropriate clinical context. The availability of novel therapeutics that target amyloid protein fibrils such as transthyretin highlights the importance of early diagnosis. Online supplemental material is available for this article. ^©RSNA, 2021.

Pulmonary amyloidosis mimicking interstitial lung disease and malignancy - A case series with a review of a pulmonary patterns

BACKGROUND

Amyloidosis is an uncommon condition, which results from accumulation of misfolded extracellular insoluble protein in tissues and organs of the body, causing its damage and dysfunction. Histologically, after staining with Congo red, the amyloid deposits show an apple-green birefringence under polarized light microscope. Amyloidosis can affect all organ systems and is classified into hereditary or acquired, localized or systemic. Respiratory involvement occurs in 50% of the patients with amyloidosis and it may take tracheobronchial, nodular parenchymal, diffuse alveolar septal and lymphatic forms.

METHODS

We report four cases of pulmonary amyloidosis. A female patient with localized form of tracheobronchial and nodular parenchymal pulmonary amyloidosis, which was initially misdiagnosed as sarcoidosis. A male patient who was referred to our department for further evaluation of multiple tumors in lungs accompanied by mediastinal lymphadenopathy, liver and peritoneal tumors. A male patient with suspect of lung malignancy. A male patient with diagnosed idiopathic pulmonary fibrosis and the possibility of malignancy.

RESULTS

All the diagnoses were established by demonstration of amyloid protein in tissue specimens obtained in transbronchial or open lung biopsies.

CONCLUSIONS

Due to its nonspecific clinical and radiological findings, amyloidosis can often mimic other diseases and should be considered as one of the differential diagnoses. In order to confirm the diagnosis, proving the presence of amyloid deposition with positive Congo red staining in respiratory specimen is mandatory.

Systemic AL amyloidosis presenting with diffuse alveolar septal involvement and respiratory failure: a case report and review of the literature

Background

Amyloidosis is the extracellular deposition of amyloid fibril protein in any tissue or organ. The clinical manifestations of pulmonary amyloidosis are variable and without specific symptoms. We report a rare case of diffuse alveolar septal amyloidosis which is an extremely rare pattern of involvement, with a very poor prognosis, to improve our understanding of the disease.

Case presentation

A 27-year-old man complained of shortness of breath and cyanosis. High-resolution computed tomography revealed diffuse ground-glass opacifications with interlobular septal thickening in both lungs. The immune-histochemistry showed monoclonal lambda light chains. This case also showed nephrotic syndrome and cardiac arrhythmia, suggesting an involvement of the kidney and the heart. Diagnosis: The diagnosis was finally established by tru-cut transthoracic sonar guided lung biopsy (TSLB), and histological examination revealed Congo red-positive amorphous eosinophilic deposits in the alveolar sept. Interventions: The patient was admitted to a respiratory intensive care unit and put on non-invasive ventilation, then discharged on domiciliary oxygen therapy, and started treatment with chemotherapy melphalan 2 mg daily plus prednisone 60 mg daily immediately after the result of histopathology. Outcomes: Three months after treatment, dyspnea and hypoxemia improved, and he continued treatment. The patient was in a good clinical condition after 10 months of follow-up, but he died suddenly.

Conclusion

As it is difficult to distinguish diffuse alveolar septal amyloidosis from other interstitial and granulomatous lung diseases because of their similar symptoms and imaging findings, thus, transthoracic sonar guided lung biopsy and histological examination is very important in the diagnosis of diffuse alveolar septal amyloidosis.

Localised laryngotracheal amyloidosis: a differential diagnosis not to forget

We present a case of multifocal laryngotracheal amyloidosis (LTA) in a 43-year-old man with persistent and progressive dysphonia and dyspnoea, and a first inconclusive histology. Although laryngeal amyloidosis accounts for fewer than 1% of all benign laryngeal tumours, it is in fact the most common site of amyloid deposition in the head, neck and respiratory tract. The clinical scenario is non-specific and diagnosis depends on a high degree of suspicion and on histology. Imaging is useful in mapping lesions, which are often more extensive than they appear during laryngoscopy. Despite being a benign entity, the prognosis is variable with a high-rate and long-latency recurrences, requiring long-term follow-up.

Amyloidosis of the respiratory system: 16 patients with amyloidosis initially diagnosed ante mortem by pulmonologists

Background

Ante mortem diagnosis of amyloidosis of the respiratory system is rare. Few data are available regarding clinical presentation, precursor proteins, diagnostic procedures, comorbidities, complications, and outcome. We assessed clinical features of a series of patients with amyloidosis of the respiratory system in two Japanese centres.

Methods

Medical records of 16 patients with amyloidosis of the respiratory system were retrospectively analysed. Amyloid was diagnosed by polarisation microscopy using Congo red-stained tissue specimens and classified immunohistochemically.

Results

Median patient age was 71 years, and median follow-up period was 5 years. Immunoglobulin light-chain (AL)-λ amyloidosis was found in eight and AL-κ in five patients. Two patients harboured wild-type transthyretin and one harboured serum amyloid A-derived amyloid. Five different forms of amyloidosis of the respiratory system were observed: nodular pulmonary amyloidosis (seven patients), diffuse alveolar-septal amyloidosis (five), mediastinal lymph node amyloidosis (three), tracheobronchial amyloidosis (one), and pleural amyloidosis (one). One patient had diffuse alveolar-septal amyloidosis and mediastinal lymph node amyloidosis. Three of five patients with diffuse alveolar-septal amyloidosis were diagnosed by transbronchial lung biopsy as having concurrent diffuse alveolar haemorrhage or pneumocystis pneumonia. Two of three patients with mediastinal lymph node amyloidosis were diagnosed by endobronchial ultrasound-guided transbronchial needle aspiration.

Conclusions

Not only nodular pulmonary amyloidosis, diffuse alveolar-septal amyloidosis, and tracheobronchial amyloidosis but also mediastinal lymph node amyloidosis and pleural amyloidosis should be considered in the differential diagnosis of amyloidosis of the respiratory system. Useful diagnostic methods include transbronchial lung biopsy for diffuse alveolar-septal amyloidosis and endobronchial ultrasound-guided transbronchial needle aspiration for mediastinal lymph node amyloidosis.

Not only nodular, diffuse alveolar-septal and tracheobronchial amyloidosis but also mediastinal lymph node and pleural amyloidosis should be considered in the differential diagnosis of amyloidosis of the respiratory systemhttps://bit.ly/2ZfZcxo

Atypical primary pulmonary amyloidosis: A rare case report

RATIONALE

Pulmonary amyloidosis is a rare respiratory disease characterized by amyloid deposition in the lungs. The clinical manifestations of pulmonary amyloidosis are variable and without specific symptoms.

PATIENT CONCERNS

We report a rare case of tracheobronchial amyloidosis to improve our understanding of the disease.

DIAGNOSES

The diagnosis of tracheobronchial amyloidosis was finally established by transbronchoscopic lung biopsy and histological examination.

INTERVENTIONS

The patient significantly improved with methylprednisolone sodium succinate for injection (40 mg/day) for 5 days and low-dose oral prednisone for 10 days.

OUTCOMES

After treatment, discomfort, such as cough, stridor, dyspnea, and chest tightness, disappeared, and he was discharged. The patient was in good clinical condition after 8 months of follow-up.

CONCLUSION

This case clearly shows that it is difficult to distinguish tracheobronchial amyloidosis from other diseases with manifestations of cough, dyspnea and chest tightness because of their similar symptoms and imaging findings. Thus, the role of transbronchoscopic lung biopsy and histological examination in the diagnosis of tracheobronchial amyloidosis is very important.

A 45-Year-Old Woman With Multiple Pulmonary Nodules and Sjögren Syndrome

CASE PRESENTATION

A 45-year-old woman presented for evaluation for 3 months of coughing and dyspnea. A recent chest CT scan done for workup of her symptoms revealed a 2-cm right-sided pulmonary nodule. She had a medical history of Sjögren syndrome, hypertension, and obesity. She also noted a weight loss of 30 lb over the last 3 years. She denied smoking, alcohol consumption, illicit drug use, or occupational exposures. A chest radiograph done 3 years prior did not reveal any pulmonary nodules. She had no personal or family history of arteriovenous malformations, hamartomas, or any malignancies and had been up to date with her breast cancer screening. She was treated with courses of hydroxychloroquine and mycophenolate mofetil for her Sjögren syndrome and did not have a history of opportunistic pulmonary infections. She denied any recent travel or exposure to TB.

Disappearing nodules: spontaneously regressing pulmonary amyloidosis

A case report of spontaneous regression of pulmonary amyloidosis, diffuse interstitial pattern, in an elderly patient.

Diffuse parenchymal pulmonary amyloidosis associated with multiple myeloma: a case report and systematic review of the literature

BACKGROUND

Pulmonary is an uncommon site of extramedullary involvement in multiple myeloma (MM). Diffuse parenchymal amyloidosis as pulmonary manifestation of MM is even rarer. We report a rare case of diffuse parenchymal pulmonary amyloidosis associated with MM diagnosed by video-assisted thoracoscopic lung biopsy (VATLB).

CASE PRESENTATION

A 58-year-old woman complained of cough and shortness of breath. HRCT disclosed diffuse ground-glass opacifications with interlobular septal thickening in bilateral lungs. A lung-biopsy sample obtained by VATLB revealed Congo Red-positive amorphous eosinophilic deposits in the alveolar septa. Surgical biopsy of abdominal wall skin and subcutaneous fat was also performed, which showed the apple-green birefringence with polarized light on Congo red stain was demonstrated in dermis. The serum immunoelectrophoresis showed monoclonal lambda light chains. A bone marrow biopsy specimen comprised 11.5% plasma cells. She was therefore diagnosed with diffuse parenchymal pulmonary amyloidosis accompanied by MM. The patient was referred to the hematology department for further chemotherapy.

CONCLUSIONS

It is important to recognize diffuse parenchymal pulmonary amyloidosis to avoid misdiagnosis.

Middle lobe syndrome: an intriguing presentation of tracheobronchial amyloidosis

Pulmonary involvement in amyloidosis is a distinct rarity. This clinical entity usually presents as tracheobronchial amyloidosis (TBA). A 32-year-old, never-smoker man presented with episodic dyspnoea and wheezing along with cough and mucoid sputum. The chest radiograph was suggestive of a middle lobe syndrome (MLS). High-resolution CT (HRCT) of the chest confirmed the presence of MLS. In addition, HRCT showed circumferential thickening of the trachea and the main bronchi, with thickening of the posterior membranous wall of trachea. Fibrebronchoscopy, done to evaluate MLS, visualised multiple small polypoidal lesions in the lower part of trachea and carina. Endobronchial biopsies showed homogeneous, acellular amorphous deposit in the subepithelial region, which was congophilic in nature. A diagnosis of TBA presenting as MLS was made. To the best of our knowledge, this is the first detailed report of MLS as a presentation of TBA in the English literature.

Hereditary Amyloidosis with Recurrent Lung Infiltrates

BACKGROUND Amyloidosis is a protein conformational disorder characterized by extracellular deposition of amyloid fibrils in extracellular tissue. Lung involvement is most commonly caused by secondary AL amyloidosis. The familial autosomal-dominant senile transthyretin (ATTR) disease manifests mainly as polyneuropathy and restrictive cardiomyopathy denoting the name familial amyloidotic polyneuropathy (FAP). Rarely, this form manifests with clinical and radiologically relevant respiratory tract symptoms and lung involvement. CASE REPORT A 51-year-old male former smoker presented with progressive lower-extremity weakness of several months' duration. He was ultimately diagnosed with chronic demyelinating polyneuropathy and treated with intravenous immunoglobulin therapy. Subsequently, he was admitted with heart failure symptoms and pulmonary infiltrates and his echocardiogram showed a 'myocardial speckled pattern', prompting an endomyocardial biopsy, which showed transthyretin amyloid deposition. He was started on diflunisal. Additionally, serial radiographic imaging of his chest over 3 different admissions for cough, dyspnea, hypoxemia, and lethargy demonstrated recurrent pulmonary infiltrates. A fiberoptic bronchoscopy with trans-bronchial biopsies revealed amyloid deposition in the lung tissue. CONCLUSIONS The clinical presentation of recurrent or persistent pulmonary symptoms and fleeting infiltrates on imaging in a patient with familial amyloidotic polyneuropathy is not common; when present, it should raise the suspicion of respiratory tract involvement.

Exercise-induced haemoptysis as a rare presentation of a rare lung disease

Amyloid primarily affecting the lungs is a seldom seen clinical entity. This case discusses the work-up of a patient presenting with exercise-induced haemoptysis and diffuse cystic lung disease on radiographic imaging. The common clinical and radiographic findings of diffuse cystic lung diseases as well as a brief overview of pulmonary amyloid are presented.