Tracheobronchial amyloidosis: evidence for local B-cell clonal expansion

Management of tracheobronchial amyloidosis: a review of the literature

Introduction

Tracheobronchial amyloidosis is a rare idiopathic disorder characterised by extracellular deposition of misfolded protein fibrils in the tracheobronchial tree. It presents with nonspecific symptoms. Deciding on the best treatment approach can be challenging due to the lack of a treatment guideline. We undertook a review to assess the therapeutic options for tracheobronchial amyloidosis and to highlight gaps within the existing evidence.

Methods

We performed a literature search from 1 January 1990 until 1 March 2022 to identify relevant literature regarding patient characteristics, symptoms, management and prognosis for patients with tracheobronchial amyloidosis.

Results

77 studies consisting of 300 patients were included. We found a great heterogeneity in the management of tracheobronchial amyloidosis patients. Although a fifth of the reported patients were managed with a wait-and-see approach, many different treatments were used as a single intervention, or multiple treatments were combined. An interesting finding is the slightly higher percentage of patients with Sjögren syndrome (n=5, 1.7%) and tracheobronchial amyloidosis compared to the normal population (0.5-1.0%).

Conclusions

There is a great heterogeneity in the management of tracheobronchial amyloidosis patients. The treatment is still based on expert opinion due to the lack of a treatment guideline. Various treatment approaches include a wait-and-see approach, external beam radiotherapy, therapeutic bronchoscopy, immunosuppressive treatment and surgery.

Amyloid Light-Chain (AL) Amyloidosis of the Trachea Associated With an Indolent B-cell Neoplasm

We report the case of a 66-year-old woman who was diagnosed with localized tracheal amyloid light-chain (AL) amyloidosis caused by an underlying B-cell neoplasm. The diagnosis was confirmed through subsequent bronchoscopy and biopsies; however, she experienced a challenging episode of hypoxic respiratory failure that required intervention. Repeat bronchoscopies showed persistent subglottic stenosis and tracheobronchomalacia, which led to tracheal debulking surgery and additional interventions. The patient's treatment began with rituximab, zanubrutinib, and dexamethasone with outpatient follow-up. The rarity of tracheobronchial amyloidosis and its connection to B-cell malignancies are highlighted, emphasizing the challenges in diagnosis and the importance of tailored treatment strategies. The patient's clinical course, characterized by atypical respiratory symptoms, delayed diagnosis, and an evolving treatment approach, underscores the complexities of managing such a rare and intricate case.

Localized Amyloidosis of the Upper Aerodigestive Tract: Complex Analysis of the Cellular Infiltrate and the Amyloid Mass

Objectives

The aim of this study was to analyse the composition of amyloid mass and the plasmacytic infiltrate of localized amyloidosis of the upper aerodigestive tract.

Methods

Biopsy materials were studied by light microscopy, immunohistochemistry (IHC), and mRNA in situ hybridization (mRNA-ISH). The amyloid mass was also analysed with high-performance liquid chromatography mass spectrometry- (HPLC-MS-) based proteomics.

Results

Nodular and diffuse forms of amyloid deposition were detected. IHC analysis revealed λ-light chain (LC) in two cases, κ-LC in one case. The remaining two were positive with both. Proteins, well known from other amyloidoses like amyloid A (AA), prealbumin/transthyretin (PA), apolipoprotein A-I (ApoAI), and amyloid P component (APC), and also keratin were found with variable intensities in the cases. HPLC-MS revealed dozens of proteins with both LCs in all the lesions but sometimes with surprisingly small intensities. mRNA-ISH analysis revealed identical λ and κ dominance and only one normal κ/λ cell ratio.

Conclusion

Cellular infiltrate and protein components in the amyloid showed congruent results in all but one case. The only exception with normal cell ratio and λ-dominant amyloid could be originated from the different protein-secreting activity of plasma cell clones. HPLC-MS analysis explored both LCs in all the amyloid in variable amount, but other proteins with much higher intensities like keratins, apolipoprotein A-IV (ApoAIV), were also detected. Proteins like AA, PA, ApoAI, and APC, previously known about amyloid-forming capability, also appeared. This indicates that localized amyloid in the upper aerodigestive tract is not a homogenous immunoglobulin mass but a mixture of proteins. The sometimes very low light chain intensities might also suggest that not all the localized amyloidosis cases of the upper aerodigestive tract are of convincingly AL type, and the analysis of the cellular infiltrate might indicate that not all are monoclonal.

The Lung in Dysregulated States of Humoral Immunity

In common variable immunodeficiency, lung manifestations are related to different mechanisms: recurrent pneumonias due to encapsulated bacteria responsible for diffuse bronchiectasis, diffuse infiltrative pneumonia with various patterns, and lymphomas, mostly B cell extranodal non-Hodgkin type. The diagnosis relies on significant serum Ig deficiency and the exclusion of any primary or secondary cause. Histopathology may be needed. Immunoglobulin (IgG) replacement is crucial to prevent infections and bronchiectasis. IgG4-related respiratory disease, often associated with extrapulmonary localizations, presents with solitary nodules or masses, diffuse interstitial lung diseases, bronchiolitis, lymphadenopathy, and pleural or pericardial involvement. Diagnosis relies on international criteria including serum IgG4 dosage and significantly increased IgG4/IgG plasma cells ratio in pathologically suggestive biopsy. Respiratory amyloidosis presents with tracheobronchial, nodular, and cystic or diffuse interstitial lung infiltration. Usually of AL (amyloid light chain) subtype, it may be localized or systemic, primary or secondary to a lymphoproliferative process. Very rare other diseases due to nonamyloid IgG deposits are described. Among the various lung manifestations of dysregulated states of humoral immunity, this article covers only those associated with the common variable immunodeficiency, IgG4-related disease, amyloidosis, and pulmonary light-chain deposition disease. Autoimmune connective-vascular tissue diseases or lymphoproliferative disorders are addressed in other chapters of this issue.

Amyloidosis of the Lung

CONTEXT

-Amyloidosis is a heterogeneous group of diseases characterized by the deposition of congophilic amyloid fibrils in the extracellular matrix of tissues and organs. To date, 31 fibril proteins have been identified in humans, and it is now recommended that amyloidoses be named after these fibril proteins. Based on this classification scheme, the most common forms of amyloidosis include systemic AL (formerly primary), systemic AA (formerly secondary), systemic wild-type ATTR (formerly age-related or senile systemic), and systemic hereditary ATTR amyloidosis (formerly familial amyloid polyneuropathy). Three different clinicopathologic forms of amyloidosis can be seen in the lungs: diffuse alveolar-septal amyloidosis, nodular pulmonary amyloidosis, and tracheobronchial amyloidosis.

OBJECTIVE

-To clarify the relationship between the fibril protein-based amyloidosis classification system and the clinicopathologic forms of pulmonary amyloidosis and to provide a useful guide for diagnosing these entities for the practicing pathologist.

DATA SOURCES

-This is a narrative review based on PubMed searches and the authors' own experiences.

CONCLUSIONS

-Diffuse alveolar-septal amyloidosis is usually caused by systemic AL amyloidosis, whereas nodular pulmonary amyloidosis and tracheobronchial amyloidosis usually represent localized AL amyloidosis. However, these generalized scenarios cannot always be applied to individual cases. Because the treatment options for amyloidosis are dependent on the fibril protein-based classifications and whether the process is systemic or localized, the workup of new clinically relevant cases should include amyloid subtyping (preferably with mass spectrometry-based proteomic analysis) and further clinical investigation.

Amyloidosis involving the respiratory system: 5-year's experience of a multi-disciplinary group's activity

Amyloidosis may involve the respiratory system with different clinical-radiological-functional patterns which are not always easy to be recognized. A good level of knowledge of the disease, an active integration of the pulmonologist within a multidisciplinary setting and a high level of clinical suspicion are necessary for an early diagnosis of respiratory amyloidosis. The aim of this retrospective study was to evaluate the number and the patterns of amyloidosis involving the respiratory system. We searched the cases of amyloidosis among patients attending the multidisciplinary rare and diffuse lung disease outpatients' clinic of Pulmonology Unit of the Hospital of Arezzo from 2007 to 2012. Among the 298 patients evaluated during the study period, we identified three cases of amyloidosis with involvement of the respiratory system, associated or not with other extra-thoracic localizations, whose diagnosis was histo-pathologically confirmed after the pulmonologist, the radiologist, and the pathologist evaluation. Our experience of a multidisciplinary team confirms that intra-thoracic amyloidosis is an uncommon disorder, representing 1.0% of the cases of rare and diffuse lung diseases referred to our center. The diagnosis of the disease is not always easy and quick as the amyloidosis may involve different parts of the respiratory system (airways, pleura, parenchyma). It is therefore recommended to remind this orphan disease in the differential diagnosis of the wide clinical scenarios the pulmonologist may intercept in clinical practice.