Abstract

INTRODUCTION
In rare instances, amyloidosis presents as a focal, macroscopic lesion involving peripheral neural tissues (amyloidoma). In all known reported cases, peripheral nerve amyloidomas have had immunoglobulin light-chain fibril composition and occurred in the context of paraproteinemia.
METHODS
A 46-year-old man presented with progressive insidious-onset right lumbosacral radiculoplexus neuropathy without paraproteinemia. MRI-targeted fascicular nerve biopsy was performed on an enlarged sciatic nerve after earlier distal fibular nerve biopsy was nondiagnostic. Laser dissected mass spectroscopy of the discovered amyloid protein was performed after immunohistochemistry failed to identify the specific amyloid protein. Complete gene sequencing of apolipoprotein A1 (ApoA1) was performed.
RESULTS
Only wild-type ApoA1 amyloid was found in the congophilic component in the nerve.
CONCLUSIONS
This case highlights the utility of MRI-guided fascicular nerve biopsy combined with laser-dissected mass spectrometric analysis. Importantly, the case expands the known causes of amyloidomas to include wild-type ApoA1.

Links

Publisher Full Text

Authors

Loavenbruck AJ, Chaudhry V, Zeldenrust SR, Spinner RJ, Theis JD, Klein CJ

Institution

Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905, USA.

Source

Muscle & nerve 46:5 2012 Nov pg 817-22

MeSH

Amino Acid Sequence
Amyloidosis
Apolipoprotein A-I
Humans
Lumbosacral Plexus
Male
Mass Spectrometry
Middle Aged
Molecular Sequence Data
Peripheral Nervous System Diseases

Pub Type(s)

Case Reports
Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

23055319