Abstract Details

Title Sural Nerve Biopsy Assessment by Individual Histologic Preparations: An Observational Cohort Study of 100 Consecutive Cases

Topic Neuromuscular and Clinical Neurophysiology (EMG)

Presentation(s) P11 - Poster Session 11 (11:45 AM-12:45 PM)

Poster/Presentation
Number 10-001

Objective

To study sural nerve biopsy utility based on different histopathologic techniques.

Background Nerve biopsies in select patients assist neuropathy diagnosis. Systematic study of their value to inform and alter treatment recommendations quantifying the value of separate histologic preparations is lacking in evidence-based practice.

Design/Methods Consecutive sural nerve biopsies (50 internal and 50 external referrals) were reviewed. Standard histological preparations plus graded teased nerve fibres (GTNF), immunohistochemistry, and epoxy-semithin morphometric analysis were studied. Nerve fibre and interstitial abnormalities were scored for each preparation by three examiners masked to case identification. Multivariate modeling was used to inform on the best combination of tests vs a gold standard of the full biopsy report plus morphometric analysis. Resulting clinicopathological diagnosis and treatment recommendations were reviewed.

Results Paraffin-stained sections best recognized interstitial abnormalities: Epineurial inflammation (n=59); vasculitis with vessel wall destruction (n=14); amyloidosis (n=2); and noncaseating granuloma (n=1). Vasculitic neuropathy associated with GTNF axonal degeneration (79%) with OR 3.8, 95%CI [1.001, 14.7], p=0.04, not significantly seen with the other preparations. Teased fibre abnormalities correlated with clinicopathologic diagnosis in demyelinated fibers in chronic inflammatory demyelinating polyradiculoneuropathy, 80% (8/10); amyloidosis, 50% (1/2); adult-onset polyglucosan disease 100% (1/1). GTNF and paraffin stains significantly correlated with fibre density determined by morphometric analysis (GTNF: OR 9.9, p<0.0001, paraffin: OR 3.8, p=0.03), not significant with semithin epoxy: OR 1.1, p=0.90, or immunohistochemistry: OR 2.4, p=0.18). GTNF combined with paraffin sections had the highest accuracy for predicting clinicopathologic diagnosis and fibre density with 0.86 C-stat prediction versus morphometric analysis. Among internal cases sural biopsy aided clinicopathologic diagnosis: immunotherapy initiation (44%); reduced immunotherapy (18%); and escalated immunotherapy (8%).

Conclusions

Sural nerve biopsy have high diagnostic utility frequently altering treatment recommendations in select patients. Paraffin stains combined with GTNF provide highest diagnostic utility, confidence, inter-rater reliability, and accuracy for diagnosis. Immunostains and epoxy sections have focused utility.

Authors/Disclosures
Pannathat Soontrapa, MD (Siriraj Hospital) PRESENTER	The institution of Dr. Soontrapa has received research support from Argenx.
Peter J. Dyck, MD, FAAN (Mayo Clinic)	Dr. Dyck has nothing to disclose.
P. James B. Dyck, MD, FAAN (Mayo Clinic)	Dr. Dyck has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Akcea/Ionis.
JaNean Engelstad	JaNean Engelstad has nothing to disclose.
	No disclosure on file
Shahar Shelly, MD (Rambam Medical Center)	Dr. Shelly has or had stock in Remepy.
William Harmsen (Mayo Clinic)	William Harmsen has nothing to disclose.
Jayawant N. Mandrekar, PhD	Dr. Mandrekar has nothing to disclose.
Robert Spinner	No disclosure on file
Cris M. Ida	Cris M. Ida, 4790 has nothing to disclose.
Christopher J. Klein, MD, FAAN (Mayo Clinic)	Dr. Klein has received personal compensation in the range of $500-$4,999 for serving as a Consultant for NMD Pharma.

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