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[Amyloid neuropathies. Histopathological study of peripheral nerve biopsy in 18 cases]
Sandrine Bouillot1, Anne Vital, Alexandre Favereaux
1Laboratoire de Neuropathologie, Université Victor Segalen, Bordeaux 2.
Objectives:
A retrospective study of nerve and muscle biopsies since 1983, with probable amyloidosis, has been performed.
Materials And Methods:
Eighteen nerve and muscle biopsies, out of 29, were selected.
Results:
Endoneurial amyloid deposits were visible on routine sections in 11 cases, revealed by ultrastructural study in 4 cases and by Congo red and/or thioflavine stains in 3 others. Amyloid deposits were marked by anti-transthyretin (TTR) serum in 13 patients, within endoneurium in 11 cases, and only around muscle fibers in 2 others. A mutation in the TTR gene, usually Val30Met, was evidenced in 8 cases and could not be assayed in the 5 others. An immunoglobulin light chain was revealed in amyloid deposits by direct immunofluorescence in the 5 other patients, of whom 4 had multiple myeloma and the fifth a lambda light chain Bence-Jones proteinuria.
Conclusion:
Nerve biopsy revealed amyloidosis in 10 patients: 5 of them had a mutation in TTR gene, without any family history.