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Peripheral nerve biopsy
1. Interpretation of Nerve Biopsy
by Dr. Sweta Biswas Das
3rd year PGT student
Department of Pathology
2. INTRODUCTION
Each peripheral nerve
composed of one or more
bundles (fascicles)
Each nerve fibre
surrounded by loose
vascular supporting tissue
endoneurium
Each fascicle surrounded
by condensed
collagenous tissue
perineurium
All fascicles are
surrounded by loose
collagenous tissue
epineurium
5. SELECTING THE NERVE FOR BIOPSY
Distal lower limbs –Sural nerve or superficial peroneal
nerve
Upper limbs-Superficial radial nerve or a branch of ulnar
nerve
Progressive optic neuropathy-Optic nerve biopsy
6. SURAL NERVE BIOPSY
Easily identifiable .
Purely sensory – No motor
deficit occur following biopsy.
Liable to be affected by
neuropathy
distal branch of a long nerve.
7. PROCESSING OF NERVE BIOPSY
1.5 2 1.5 5 cm
Neutral-buffered formalin 4 % Glutaraldehyde -180°C liquid Nitrogen
Paraffin section Semithin section
Thin section for EM
Frozen section
H&E
Modified trichrome
Congo red
Toluidine blue
Toluidine blue and
basic fuchsin
H&E
Modified trichrome
Congo red
Cresyl-fast-violet
8. Advantages and Disadvantages of tissue Sections
Frozen section Rapid diagnosis
Immunofluorescent studies
Relative ease for preserving
the longitudinal section for
segmental demyelination
Detail of the cells are not
clear
Paraffin section Details of cell and
anatomical structure
Artifact is unavoidable
Semithin section Detection thinly myelinated
fibers
Detection of onion bulb
Detection clustering of
regenerated fibers
Special training
EM section
The only test for the
unmyelineated fibers
Special training
9. STANING
Different stains Staining for
H&E Morphology, Vasculitis, Inflammation,
Myelin ovoids, axonal degeneration
Masson's Trichrome Fibrosis, Hyalinisation,Vessels
Luxol fast blue Myelin
Toluidine Myelin
Congo red Amyloid
IHC EMA ,S100,MBP,PMP22
13. WHAT TO LOOK FOR
Status of the epineurium including the blood vessels
Alterations in the perineurium
Endoneurium oedema
Density of the large and small myelinated nerve fibers
Extent of axonal degeneration and atrophy
Frequency of bands of Bungner and Myelin
degeneration
Number of macrophages cluster
Onion bulb formation
Inflammatory infiltrates
Presence/absence of amyloid
14. Wallerian degeneration
Degeneration of axon
distally following its
interruption
Distal to injury the axon
disintegrates and the myelin
breaks up into globules
Macrophages participate in
the removal of axonal and
myelin debris
Approximation of nerve
ends result in regeneration,
the basement membrane
of the schwann cell survives
and acts as skeleton along
which the axon regrows
15. SEGMENTAL DEMYELINATION
Scattered destruction
of the myelin sheath
occurs without axonal
damage
The primary lesion
affects the schwann
cell. Prognosis for
recovery is good
because the muscle is
not denervated
17. ONION BULB FORMATION
Refers to the concentric laminated layers surrounding
the nerve fibre.
Best detected in the semithin section
Pathogenetically , onion bulb formation is indication of
repeated demyelination and remyelination
19. INFLAMMATORY DEMYELINATING
POLYNEUROPATHY
Acute- Guillain Barré Syndrome
Acute onset immune mediated demyelinating
neuropathy
Weakness beginning in the distal limbs and rapidly
advances to affect proximal muscle function(ascending
paralysis)
Prior history of viral infection
Hallmark of inflammatory neuropathy- presence of
inflammatory cells in the endoneural space of the nerve
Inflammatory cells are primarily responsible for the
macrophage induced demyelination in these neuropathy
20. Chronic inflammatory Demyelinating Poly
radiculoneuropathy
Symmetrical mixed sensorimotor polyneuropathy that
persists for more than 2 months
Evidence of recurrent demyelination and remyelination
associated with proliferation of Schwann cells
,formation of onion bulbs
INFLAMMATORY DEMYELINATING
POLYNEUROPATHY
22. LEPROSY
M. leprae is the bacterium that invades peripheral
nerve
Common nerves are
Ulnar nerve at the elbow
Deep peroneal branch at the ankle
23. TUBERCULOID LEPROSY
Pathological hallmark is an intense inflammatory
granulomatous lesion that severely damages the neural
architecture
Axon ,schwann cells and myelin lost
Granulomas in the epineural and perineural spaces &
edoneural space.
Bacilli are scanty ,
Localized nerve involvement
Healing –fibrosis and hyalization in the endoneurium
and thick perineurial and epineurial sheaths
25. LEPROMATOUS LEPROSY
Perineural and endoneural infiltration of enlarged
macrophages and Schwann cells with M leprae bacilli
and inflammatory cells.
In severe cases the epineurium may be infiltrated by
huge numbers of foamy cells especially around blood
vessels.
Granulomatous inflammatory response minimal.
Segmental demyelination and remyelination and loss of
both myelinated and unmyelinated axon
Symmetric polyneuropathy
27. DIABETIC NEUROPATHY
Ascending distal symmetric sensorimotor
polyneuropathy
Patients may be both type 1 and type 2
Nerve biopsy show reduced numbers of axons,
degenerating myelin sheaths and regenerative axonal
clusters,
Endoneurial arterioles show thickening ,hyalinization
33. AMYLOID NEUROPATHY
Neuropathies are usually distally accentuated and
symmetrical, and multiple mono neuropathies may
occur
Predominantly of axonal type
Amyloid may be deposited within endoneurium ,and
epineurial vasculature
Stain-Congo red and Thioflavin S or T