[History of the study of amyloidosis: from the Rokitansky's theory to the present day].

In the history of amyloidosis studying the concept of liquids dyscrasia has been predominated and finally it is resulted in accepting a serum protein-precursor as a leading amyloidogenic factor in the disease pathogenesis. Consequently basic diagnostic and treatment strategy was aimed to find and eliminate this protein from the blood and this approach evidenced high effectiveness in most frequent AA and AL-amyloidosis characterized with anomaly high levels of precursors in the blood. At the same time there are less frequent and slower progressing inheritant forms of systemic amyloidosis including transthyretin induced, which are less depending on amyloidogenecity of amyloid precursor and because of that, in example, the effectiveness of transthyretin stabilizers or blockers of its synthesis is limited comparing with the precursor elimination in AA or AL. Developed in the middle of XX century a theory of local synthesis by macrophages is more preferable to describe the pathogenesis of these forms. And modern proteome analysis using give rise to confirm the key meaning of macrophage in the amyloidogenesis and proves necessity to know deeply mechanisms of macrophagial autophagia - basic tool of maintaining intracellular protein homeostasis. That is why it is difficult to hope on high effectiveness of chemical amyloid solvents in vivo, which being under macrophages regulation never could realize its chemical activities.

[Renal leukocyte chemokine type 2 amyloidosis: a clinicopathological analysis of fifteen cases].

Objective: To investigate the clinicopathological features of renal leukocyte chemokine type 2 amyloidosis (ALECT2). Methods: The prevalence, clinical characteristics, renal histopathological features, and renal outcome of 15 patients with ALECT2 by kidney biopsy were collected in the Department of Kidney Pathology, Shanxi Medical University Second Hospital, Taiyuan, China from January 1993 to December 2023. Immunohistochemistry and mass spectrometry for amyloid proteins were carried out. Results: Fifteen patients with ALECT2 were included in the study, representing 12.93% (15/116) of the renal biopsy-proven amyloidosis cases. There were 5 males and 10 females. The median age at diagnosis was 61 years. All patients had various degrees of proteinuria; 7 patients had nephrotic syndrome; 3 patients had renal insufficiency; 7 patients had microscopic hematuria. Renal biopsy showed that strongly orangophilic amyloid proteins distributed mainly in the renal cortical interstitium, vascular walls, the glomerular mesangium and/or glomerular basement membrane. Eight cases were diagnosed with ALECT2 alone and 7 cases combined with other renal diseases, including 4 cases with membranous nephropathy, 2 cases with IgA nephropathy, and 1 case with subacute tubular interstitial nephropathy. ALECT2 patients with concurrent renal disease showed a higher proteinuria level than those without (3.48 g/24 h versus 4.58 g/24 h). All patients were corroborated by immunohistochemistry to exhibit the specific location of LECT2 in the amyloid fibrils. Mass spectrometry analysis revealed LECT2 polypeptide in 9 patients. Except two patients with worsening renal function, the others showed stable renal function during the mean follow-up period of 12.5 months. Conclusions: ALECT2 is the second common type of renal amyloidosis in our center. The majority of ALECT2 patients show concurrent renal diseases, with a high rate of membranous nephropathy. Amyloid deposits distribute mainly in the cortical interstitium of the kidney, the glomerular mesangium and vascular walls. Mass spectrometry is the most sensitive and specific method for detecting LECT2 amyloidosis.

Advancements and challenges in cardiac amyloidosis imaging: A comprehensive review of novel techniques and clinical applications.

Cardiac amyloidosis, characterized by amyloid fibril deposition in the myocardium, leads to restrictive cardiomyopathy and heart failure. This review explores recent advancements in imaging techniques for diagnosing and managing cardiac amyloidosis, highlighting their clinical applications, strengths, and limitations. Echocardiography remains a primary, non-invasive imaging modality but lacks specificity. Cardiac MRI (CMR), with Late Gadolinium Enhancement (LGE) and T1 mapping, offers superior tissue characterization, though at higher costs and limited availability. Scintigraphy with Tc-99m-PYP reliably diagnoses transthyretin (TTR) amyloidosis but is less effective for light chain (AL) amyloidosis, necessitating complementary diagnostics. Amyloid-specific PET tracers, such as florbetapir and flutemetamol, provide precise imaging and quantitative assessment for both TTR and AL amyloidosis. Challenges include differentiating between TTR and AL amyloidosis, early disease detection, and standardizing imaging protocols. Future research should focus on developing novel tracers, integrating multimodality imaging, and leveraging AI to enhance diagnostic accuracy and personalized treatment. Advancements in imaging have improved cardiac amyloidosis management. A multimodal approach, incorporating echocardiography, CMR, scintigraphy, and PET tracers, offers comprehensive assessment. Continued innovation in tracers and AI applications promises further enhancements in diagnosis, early detection, and patient outcomes.

Nasopharyngeal amyloidoma: report of three cases and review of the literature.

BACKGROUND: Nasopharyngeal amyloidoma is a rare, locally aggressive tumor that has been reported in the English literature in only 38 cases to date, most of which were in the form of case reports. The present study was aimed to summarize the characteristics of this rare tumor, with the goal of providing new insights for diagnosis and treatment. MATERIALS AND METHODS: We report three cases of nasopharyngeal amyloidoma diagnosed in our hospital following comprehensive medical examination and review the current literature on all cases of nasopharyngeal amyloidoma from PubMed. The journey of nasopharyngeal amyloidoma, including presentation, diagnostics, surgeries, and follow-up was outlined. RESULTS: None of the three patients had systemic amyloidosis. CT and nasal endoscopy showed irregular masses obstructing the nasopharyngeal cavity. Congo red staining confirmed the deposition of amyloid, and immunohistochemical analysis showed that the amyloid deposition was the AL light chain type. Through literature review, we found that nasopharyngeal amyloidoma most commonly occurred in individuals over the age of 40, patients usually had a good prognosis after complete tumor resection; however, there were still cases of recurrence, and unresected patients were at risk of progression to systemic amyloidosis. The efficacy of radiotherapy and chemotherapy was currently uncertain. CONCLUSION: Early clinical and pathological diagnosis is crucial, and surgical intervention is the primary treatment option for this disease. Although patients usually have a favorable prognosis, long-term monitoring is necessary to detect potential relapses and initiate timely intervention.

Immunohistochemical Diagnosis of Amyloid Typing: Utility and Limitations as Determined by Liquid Chromatography-Tandem Mass Spectrometry.

BACKGROUND: Although immunohistochemical techniques and proteomic analysis are widely used for typing diagnosis of amyloidosis, the diagnostic utility of immunohistochemical evaluation is not well understood. METHODS: We used immunohistochemical techniques to characterize staining patterns of in-house rabbit polyclonal anti-κ, anti-λ, anti-transthyretin antibodies, and commercial anti-amyloid A and anti-ß2-microglobulin antibodies in 40 autopsy cases. RESULTS: In thirty cases (75%), the subtype was determined by using the criterion that amyloid is strongly and diffusely positive for one antibody while negative for other antibodies. We then performed proteomic analysis of all 40 cases. In 39 cases, we identified only one amyloid protein and confirmed the immunohistochemically determined subtypes of the abovementioned 30 cases. In seven other cases, we could retrospectively determine subtypes with immunohistochemistry by using information from proteomic analysis, which increased the immunohistochemistry diagnosis rate to 92.5% (37/40). In one case, we identified double subtypes, both immunohistochemically and with proteomic analysis. In the remaining three cases, proteomic analysis was essential for typing diagnosis. CONCLUSIONS: The present findings suggest that combined immunohistochemistry and proteomic analysis is more useful than immunohistochemistry alone. Our findings highlight the importance of carefully interpreting immunohistochemistry for anti-TTR and light chain and offer insights that can guide amyloid typing through immunohistochemistry.

Concurrent Acute Heart Failure and Renal Failure in Amyloid Light Chain Amyloidosis.

INTRODUCTION: Amyloid light chain (AL) amyloidosis is a multisystem disease with significant variability in patient presentation. This case describes the presentation and workup of a patient with unique multiorgan involvement on initial presentation. CASE PRESENTATION: A 69-year-old African American male presented with weakness, leg swelling, and shortness of breath. Initial workup demonstrated acute heart failure and acute-on-chronic renal failure with nephrotic range proteinuria (5.78 protein to creatinine ratio). Further workup showed elevated serum protein electrophoresis, urine protein electrophoresis, and light chains. Subsequent renal biopsy showed lambda-restricted AL-type renal amyloidosis. DISCUSSION: A variety of systemic presentations have been described in the literature; however, concurrent heart and renal failure as primary presentation is uncommon. CONCLUSIONS: This case emphasizes the importance of considering systemic inflammatory diseases, such as amyloidosis, in the differential diagnoses of patients with unexplained multiorgan disease. Early diagnosis and treatment initiation are essential for improving patient outcomes. Improved recognition of common clinical manifestations and laboratory abnormalities will likely improve outcomes through earlier diagnosis.

Multiple myeloma with secondary amyloidosis: Dysphagia as the first symptom: A case report.

RATIONALE: Multiple myeloma (MM) with secondary amyloidosis (AL) is a rare clonal plasma cell proliferation disease, which causes dysfunction of multiple organs and tissues. We report a case of dysphagia as the first symptom in a patient with MM and secondary AL. PATIENT CONCERNS: The patient was a 73-year-old female, was admitted to our hospital, because of progressive dysphagia for 4 months and limb weakness for 1 month. DIAGNOSES: The bone marrow smear and pathology diagnosis revealed the presence of MM, while the biceps myopathy diagnosis indicated AL. INTERVENTIONS: The VCD regimen consisted of bortezomib at a dosage of 1.9 mg on days 1, 8, 15, and 22, cyclophosphamide 0.4 g on days 1, 8, and 15, and dexamethasone at a dosage of 40 mg on days 1, 8, 15, and 22. The patient simultaneously received comprehensive treatment including anti-infective therapy, enhanced cardiac function, and nutritional support. OUTCOMES: The M protein in the blood and urine protein were negative, indicating a reduction in bone marrow plasma cells to 2%. Flow cytometric analysis revealed a minimal percentage 0.04%. As a result, complete remission was achieved. LESSONS: The clinical manifestations of MM exhibit a wide range, with the symptoms of secondary injury causing significant disturbing, while the atypical symptoms of extramedullary manifestations pose challenges in diagnosing the disease.

Cardiac magnetic resonance findings in cardiac amyloidosis.

PURPOSE OF REVIEW: The purpose of this review is to highlight the increasing importance of cardiac magnetic resonance (CMR) imaging in diagnosing and managing cardiac amyloidosis, especially given the recent advancements in treatment options. RECENT FINDINGS: This review emphasizes the crucial role of late gadolinium enhancement (LGE) with phase-sensitive inversion recovery (PSIR) techniques in both diagnosing and predicting patient outcomes in cardiac amyloidosis. The review also explores promising new techniques for diagnosing early-stage disease, such as native T1 mapping and ECV quantification. Additionally, it delves into experimental techniques like diffusion tensor imaging, MR elastography, and spectroscopy. SUMMARY: This review underscores CMR as a powerful tool for diagnosing cardiac amyloidosis, assessing risk factors, and monitoring treatment response. While LGE imaging remains the current best practice for diagnosis, emerging techniques such as T1 mapping and ECV quantification offer promise for improved detection, particularly in early stages of the disease. This has significant implications for patient management as newer therapeutic options become available for cardiac amyloidosis.

Nuclear imaging techniques for cardiac amyloidosis.

PURPOSE OF REVIEW: Cardiac amyloidosis is a condition marked by the misfolding of precursor proteins into insoluble amyloid fibrils, leading to restrictive cardiomyopathy and heart failure symptoms. This review discusses advancements in nuclear imaging techniques that enhance the diagnosis and guide the management of cardiac amyloidosis, addressing the critical need for early and accurate detection in clinical practice. RECENT FINDINGS: Recent studies and guidelines emphasizes the pivotal role of nuclear imaging techniques in diagnosing cardiac amyloidosis. Cardiac scintigraphy, using bone-avid tracers like 99mTc-PYP, 99mTc-DPD, and 99mTc-HMDP, is instrumental in distinguishing between transthyretin amyloidosis and light chain amyloidosis. PET, with tracers such as 11C-Pittsburgh Compound B (11C-PiB) and 18F-Florbetapir, offers significant potential in measuring amyloid burden and monitoring disease progression, providing detailed insights into the myocardial involvement. SUMMARY: The advancements in nuclear imaging techniques significantly impact the management of cardiac amyloidosis. These methods allow for a more accurate diagnosis, detailed assessment of disease extent, and better differentiation between amyloidosis types, which are crucial for tailoring treatment approaches. The integration of these techniques into clinical practice is essential for improving patient outcomes and advancing research in cardiac amyloidosis.

Clinical analysis of 37 Chinese patients with ocular amyloidosis: a single center study.

OBJECTIVE: To examine the clinical characteristics, diagnosis and treatment, and prognosis of ocular amyloidosis in a Chinese population. METHODS: A retrospective case series study was conducted. The clinical data of 37 patients with ocular amyloidosis were collected and the clinical characteristics, diagnosis and treatment, and prognosis were summarized and analyzed. RESULTS: The 37 patients included 12 males and 25 females ranging in age from 22 to 75 years, with median age of 49 years. The clinical signs and symptoms included a conjunctival mass in 37 patients (100%), periorbital discomfort or pain in 29 patients (61.9%), ptosis in 18 patients (23.8%), exophthalmos or eyeball displacement in 3 patients (14.3%), restricted eye movement in 2 patients (9.52%), vision loss in 1 patient (4.76%), and diplopia in 1 patient (4.76%). A total of 29 patients had only conjunctival involvement and 8 patients had concomitant orbital and conjunctival involvement. The main treatment for patients with conjunctival involvement was surgical resection. Thirty-one patients had stable disease, 4 patients progressed or relapsed, and 2 patients were lost to follow-up. CONCLUSION: Ocular amyloidosis most commonly presents as an eyelid or conjunctival mass or diffuse thickening and can also present as an orbital mass. Diagnosis is mainly dependent on histopathological examination. Surgery is the main treatment and is done to confirm the diagnosis to guide further treatment, preserve function, and prevent complications that threaten visual acuity. Close postoperative follow-up is necessary.

Non-Immunoglobulin Amyloidosis-Mediated Kidney Disease: Emerging Understanding of Underdiagnosed Entities.

Amyloidosis is a complex group of rare disorders characterized by the deposition of misfolded proteins in the extracellular space of various tissues and organs, leading to progressive organ dysfunction. The kidneys constitute a very common site affected, most notably by immunoglobulin-mediated (light chain, heavy chain, and light and heavy chain amyloidosis), but other types that include serum amyloid A (AA) amyloidosis and leukocyte chemotactic factor 2 amyloidosis, along with mutant proteins in several hereditary forms of amyloidosis such as transthyretin, fibrinogen α-chain, gelsolin, lysozyme, and apolipoproteins AI/AII/AIV/CII/CIII amyloidosis have been incriminated as well. The clinical presentation is variable and can range from minimal proteinuria for leukocyte chemotactic factor 2 amyloidosis to a full-blown nephrotic syndrome for AA amyloidosis. Clinical correlation, genetic analysis, and adequate tissue typing through a kidney biopsy are essential to make the correct diagnosis, especially when a family history of amyloidosis is absent. Except for AA and transthyretin amyloidosis, the treatment is usually purely supportive. Kidney transplantation is an acceptable form of treatment for end-stage kidney disease in all types of non-Ig-mediated renal amyloidosis.

Paraprotein-Mediated Glomerular Diseases.

Paraproteinemias are a group of complex diseases associated with an overproduction of a monoclonal immunoglobulin that can cause a diversity of kidney disorders and end-organ damage. In this review, we focus on paraprotein-mediated glomerular diseases. Kidney biopsy plays a crucial role in diagnosing these disorders, enabling the identification of specific histological patterns. These lesions are categorized into organized (such as amyloidosis, immunotactoid glomerulopathy, fibrillary glomerulonephritis, cryoglobulinemic glomerulonephritis, and monoclonal crystalline glomerulopathies) and nonorganized deposits (such as monoclonal Ig deposition disease and proliferative glomerulonephritis with monoclonal Ig deposits) based on the characteristics of immunofluorescence findings and the ultrastructural appearance of deposits on electron microscopy. This review aims to provide an update, highlight, and discuss clinicopathological aspects such as definition, epidemiology, clinical manifestations, mechanisms of kidney injury, histological features, and diagnostic procedures.

Cutaneous amyloidosis mimicking basal cell carcinoma: a case series and literature review.

BACKGROUND: Amyloidosis is characterized by extracellular amyloid protein deposition. When amyloidosis intersects with basal cell carcinoma (BCC), it introduces complex diagnostic challenges. This study explored the overlap between primary localized cutaneous amyloidosis (PLCA) and BCC, examining amyloid deposits in BCC, systemic amyloidosis risk in PLCA, and various treatment methods. METHODS: Two case studies were discussed, followed by a literature review, in which PubMed, Web of Science, EMBASE, and the Cochrane Library databases were utilized. The search, covering studies from infinity up to January 2024, focused on "cutaneous amyloidosis," "basal cell carcinoma," and related terms. Articles in English detailing the clinical presentation, diagnostic methods, treatment, and outcomes of cutaneous amyloidosis mimicking BCC were included. Data extraction and synthesis were performed by two independent reviewers. CASE SERIES: This study highlighted two cases exemplifying the complexity of diagnosing BCC and PLCA. The first case (a 64-year-old with a nodule on the cheek) and the second (a 67-year-old with a nodular lesion on the upper lip cheek) were initially suspected as BCC and were later identified as PLCA upon histopathological examination. DISCUSSION: The diagnosis of amyloidosis within BCC nodules remains a diagnostic challenge. Although their coexistence is relatively prevalent, their local recurrence rates remain debatable. Various diagnostic and therapeutic approaches have been suggested, such as topical creams and phototherapy. However, none have garnered conclusive and consistent evidence to establish reliable clinical application. CONCLUSION: The findings emphasized the importance of considering alternative pathologies in differential diagnoses. Future research should focus on understanding systemic amyloidosis risks and optimizing care for both conditions.

A case of hypopharyngeal amyloidosis by digestive endoscopy. / æ¶ˆåŒ–å† é•œæ£€æŸ¥å‘çŽ°ä¸‹å’½éƒ¨æ·€ç²‰æ ·å˜æ€§1例.

Amyloidosis is a rare disease. This paper reports a case of localized secondary hypopharyngeal amyloidosis presenting with pulmonary tuberculosis as the initial symptom. The patient lacked specific clinical manifestations and primarily exhibited symptoms such as cough, sputum production, acid reflux, belching, and abdominal pain. Chest CT indicated bronchiectasis with infection and pulmonary tuberculosis. Digestive endoscopy revealed a white mucosal elevation at the right pyriform sinus of the hypopharynx. Pathological diagnosis confirmed amyloid deposits in the hypopharyngeal mucosal tissue. The patient tested positive for anti-amyloid A antibodies, Congo red staining (+), and periodate Schiff staining (+). Amyloidosis commonly affects the digestive system and may have various etiologies, often presenting with symptoms that overlap with other digestive system diseases, leading to frequent misdiagnosis and missed optimal treatment opportunities. The hypopharynx, a highly folded and narrow chamber that serves as a common passage for the digestive and respiratory tracts, can be effectively evaluated for amyloidosis using digestive endoscopy.

The Most Predictive Red Flags for Suspecting Cardiac Amyloidosis in Patients with Heart Failure with Preserved Ejection Fraction.

OBJECTIVE: Cardiac amyloidosis (CA) is a cardiomyopathy characterized by amyloid infiltration in the myocardium. Transthyretin cardiac amyloidosis (TTR-CA), commonly presenting as heart failure with preserved ejection fraction (HFpEF), was the focus of our study, which aimed to identify red flags that heighten suspicion of CA in HFpEF patients. METHODS: We prospectively included patients diagnosed with HFpEF. All patients were assessed for TTR-CA red flag features, cardiac and extra-cardiac, as outlined in the 'Diagnosis and Treatment of Cardiac Amyloidosis: A Position Statement of the European Society of Cardiology.' Technetium-99m pyrophosphate (99mTc-PYP) cardiac scintigraphy was performed in 167 HFpEF patients suspected of having TTR-CA. Patients testing positive and negative for TTR-CA were compared based on these red flag features. RESULTS: Out of 167 HFpEF patients, 19 (11.3%) were diagnosed with TTR-CA. In the TTR-CA group, 17 (89.5%) patients were 65 years or older. The presence of three or more red flags differentiated the TTR-CA positive and negative groups (P = 0.040). Features such as low voltage and pseudo infarct patterns were more prevalent in the TTR-CA group (P < 0.001 and P < 0.048, respectively). Left ventricular global longitudinal strain (LV-GLS) was lower in the TTR-CA positive group (P < 0.001). Multivariate analysis identified four variables-older age, pseudo infarct pattern, low/decreased QRS voltage, and LV-GLS-as strong, independent predictors of TTR-CA, with significant odds ratios (ORs) of 7.8, 6.8, 16.9, and 1.2, respectively. CONCLUSION: In this study, TTR-CA etiology occurs in approximately one in every ten HFpEF patients. The presence of three or more red flags increases the likelihood of TTR-CA. Older age, pseudo infarct pattern, low/decreased QRS voltage, and reduced LV-GLS are the most significant red flags indicating TTR-CA in HFpEF patients.

Advancing Renal Amyloidosis Care: The Role of Modern Diagnostic Techniques with the Potential of Enhancing Patient Outcomes.

Renal amyloidosis is a set of complex disorders characterized by the deposition of amyloid proteins in the kidneys, which causes gradual organ damage and potential kidney failure. Recent developments in diagnostic methods, particularly mass spectrometry and proteome profiling, have greatly improved the accuracy of amyloid typing, which is critical for disease management. These technologies provide extensive insights into the specific proteins involved, allowing for more targeted treatment approaches and better patient results. Despite these advances, problems remain, owing to the heterogeneous composition of amyloid proteins and the varying efficacy of treatments based on amyloid type. Access to sophisticated diagnostics and therapy varies greatly, highlighting the global difference in renal amyloidosis management. Future research is needed to investigate next-generation sequencing and gene-editing technologies, like clustered regularly interspaced short palindromic repeats (CRISPR), which promise more profound insights into the genetic basis of amyloidosis.

[Cardiac amyloidosis and aortic stenosis: what do we know?] / Amiloidosi cardiaca e stenosi valvolare aortica: quale legame?

Aortic valve stenosis and cardiac amyloidosis, particularly transthyretin-related, often coexist and share a common clinical and demographic profile. Several pathophysiological hypotheses have been proposed regarding the causes of this association, neither of which fully substantiated in practice. The key to detect the coexistence of cardiac amyloidosis and aortic valve stenosis lies in clinical suspicion. It is possible to hypothesize concurrent cardiac amyloidosis in patients with aortic valve stenosis with the aid of clinical, electrocardiographic, echocardiographic, and extracardiac "red flags". Subsequent non-invasive diagnostic steps are often sufficient to establish a definitive diagnosis. The early diagnosis of this condition is pivotal since the presence of dual pathology worsens patient's prognosis, especially without intervention. Available data on treatment show a better outcome in terms of survival and cardiovascular events in patients undergoing percutaneous correction of valvular heart disease rather than medical therapy alone, regardless of the presence of cardiac amyloidosis. Furthermore, it seems that cardiac amyloidosis does not impact survival after transcatheter aortic valve replacement, even if higher rates of rehospitalizations have been described. Indeed, percutaneous treatment of valvular heart disease is currently considered the primary therapeutic option. Subsequently a disease-modifying treatment for transthyretin amyloidosis may be considered in order to delay disease progression and improve outcomes, even if specific data are still lacking.

Clinical Use of Biomarkers in Cardiac Amyloidosis.

Amyloidosis is a systemic condition characterized by multiple organs involvement. A multidisciplinary and multimodal approach in assessing patients is pivotal and recommended by the international scientific societies. Biomarkers represent an essential noninvasive tool to increase the suspicion of disease and orient further workup and clinical management of patients. This review provides an updated contemporary focus on the clinical use of biomarkers in cardiac amyloidosis, emphasizing their role in both the diagnostic and prognostic setting and discussing future perspective of emerging biomarkers.

Systemic Diseases and Heart Block.

Systemic diseases can cause heart block owing to the involvement of the myocardium and thereby the conduction system. Younger patients (<60) with heart block should be evaluated for an underlying systemic disease. These disorders are classified into infiltrative, rheumatologic, endocrine, and hereditary neuromuscular degenerative diseases. Cardiac amyloidosis owing to amyloid fibrils and cardiac sarcoidosis owing to noncaseating granulomas can infiltrate the conduction system leading to heart block. Accelerated atherosclerosis, vasculitis, myocarditis, and interstitial inflammation contribute to heart block in rheumatologic disorders. Myotonic, Becker, and Duchenne muscular dystrophies are neuromuscular diseases involving the myocardium skeletal muscles and can cause heart block.

Rapidly progressive myopathy: unveiling light chain amyloidosis as an initial manifestation of multiple myeloma: a case report and literature review.

We present the case of a 79-year-old man with rapidly progressive myopathy as the initial manifestation of light chain amyloidosis associated with multiple myeloma. The patient experienced progressive lower limb weakness resulting in difficulty climbing stairs. Ancillary tests revealed slightly elevated serum creatine kinase levels. The electromyogram revealed a diffuse myogenic pattern while muscle MRI indicated fatty replacement of the quadriceps muscles. Muscle biopsy revealed the presence of amyloid deposits in the vessel walls. An elevated level of lambda (246 mg/L) light chain was detected. The bone marrow aspiration results were consistent with the diagnosis of multiple myeloma. In conclusion, even if amyloid myopathy is a rare condition, routine screening for amyloid deposits in muscle biopsy is crucial and should be performed systematically. In the present case, it enabled a rapid diagnosis and the beginning of treatment.