Interstitial amyloidosis in sporadic inclusion body myositis
| Autor: | Mazen Alamr, Steven R. Ytterberg, Elie Naddaf, Teerin Liewluck, Stephanie J Steel, Lyell K. Jones, Margherita Milone |
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| Rok vydání: | 2021 |
| Předmět: |
Amyloid
Pathology medicine.medical_specialty Physiology Autopsy Monoclonal Gammopathy of Undetermined Significance Myositis Inclusion Body Cellular and Molecular Neuroscience Physiology (medical) Biopsy medicine Humans Immunoglobulin Light-chain Amyloidosis Pathological Amyloid Neuropathies Familial Muscle biopsy medicine.diagnostic_test biology business.industry Amyloidosis medicine.disease Transthyretin Peripheral neuropathy biology.protein Neurology (clinical) business |
| Zdroj: | Muscle & Nerve. 64:590-594 |
| ISSN: | 1097-4598 0148-639X |
| DOI: | 10.1002/mus.27362 |
| Popis: | Introduction/aims Intracellular congophilic inclusions within muscle fibers, although nonspecific, are one of the pathological hallmarks of sporadic inclusion body myositis (sIBM). Extracellular amyloid deposits in muscle, on the other hand, are the canonical findings of amyloid myopathies, which occur with or without systemic amyloidosis. Methods We reviewed the muscle biopsy database (1998-2020) to identify sIBM patients with extracellular amyloid deposits. Clinical and laboratory data were reviewed. Results We identified five sIBM patients (three clinicopathologically defined and two clinically defined) with extracellular amyloid deposits in muscle. Mean age at diagnosis was 74.8 y (range, 68-84 y). All patients had a typical sIBM pattern of weakness without associated sensory or autonomic symptoms. None had electrophysiological evidence of peripheral neuropathy. Only one patient had a monoclonal gammopathy (immunoglobulin M-lambda, IgM-λ) with normal bone marrow biopsy. This patient with monoclonal gammopathy and three other patients underwent abdominal fat pad aspirate and were negative for amyloid. Cardiac evaluation was unrevealing in the four patients tested. Three patients without monoclonal gammopathy had normal transthyretin gene sequencing and inconclusive mass spectrometry-based analysis. The patient with monoclonal gammopathy died of pneumosepsis 5 y after diagnosis and autopsy revealed multi-organ transthyretin amyloidosis. Discussion Detection of extracellular amyloid deposition in muscle should trigger an aggressive search for systemic amyloidosis independently from other associated myopathological abnormalities. Amyloid subtyping is crucial for early therapy and mortality prevention. An isolated monoclonal gammopathy should not halt a search for non-hematological causes of systemic amyloidosis. |
| Databáze: | OpenAIRE |
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