Thank you to: L Magy, L Richard, N Couade, F Maquin

Transcription

1 «Crash course in the interpretation of peripheral nerve biopsies: which nerve to biopsy, tissue fixation: paraffin, semi thins, EM (common stains and immunos), identifying degenerating and regenerating axons, myelin, Schwann cells vs fibroblasts, onion bulbs» Thank you to: L Magy, L Richard, N Couade, F Maquin

2 NERVE BIOPSY INTRODUCTION The diagnosis of a peripheral neuropathy is essentially based on clinical data Electrophysiological findings are often useful In routine practice, only a few cases will require biopsy

3 NERVE BIOPSY MAY BE STILL VERY USEFUL TECHNIQUES: - Which nerve? - Optic microscopy Immuno - Electron microscopy Immuno RESULTS: - Normal - Lesions: myelin axon interstitial tissue others: toxic, infection

4 WHICH NERVE? The nerve selected for biopsy should be clinically and/or electrophysiologically affected. Standard distal whole cutaneous sensory nerve biopsies (mostly sural). In fact, any sensory nerve can be biopsied. The superficial radial nerve may be taken when symptoms predominate in the upper limbs. Sometimes a biopsy of the superficial peroneal nerve may be required as fragments from the adjacent peroneus brevis muscle may be taken by the same incision, especially, when the clinician is looking for a process which may be of patchy distribution such as vasculitis, amyloidosis. In selected situations, nerve biopsy may be guided by imaging, as it is the case for rootlet or plexus biopsy. Skin biopsy: study of intra-epidermic unmyelinated fibers (painful neuropathy). in the dermis, only very few myelinated fibers, not well orientated for microscopical studies.

5 Superficial radial nerve 1st perforatng nerve (crural) Superficial peroneal nerve Peroneus brevus muscle Sural

6 TO UNDERSTAND THE INTERPRETATION OF A NERVE BIOPSY TECHNIQUES RESULTS Formalin 10% Paraffin - Interstitial tissue Vasculitis cellular infiltrates deposits... Glutaraldehyde-buffer «Teasing» Epon : - semi-thin (optic) - ultra-thin (EM) - myelinated fibers - unmyelinated fibers - other structures LRW : immuno EM - specific immunolabellings Frozen - Abnormal deposits : (isopentan) Immunopathology: immunoglobulins amyloidosis - Immunotyping of cells Non pathological studies: - DNA extraction - Clonality of cell infiltrates Fresh material Vibratome - Biochemical analysis Immunopathology EM: electron microscopy LRW: London Resin White

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11 Schmidt Lanterman incisure

12 RANVIER NODE CONTROL AXO-GLIAL JUNCTION node Transverse bands loop AXON paranode AXON MYELIN

13 AXON BASAL MEMBRANE nucleus SC F mitochondria MYELIN R er collagen

14 Renaut bodies

15 capillary mast cell

16 p e r i n e u r i a l c e l l capillary Perineurial cells SC

17 IgM myelin deposits

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19 J Peripher Nerv Syst Jun;7(2): LR white post-embedding colloidal gold method to immunostain MBP, P0, NF and S100 in glutaraldehyde fixed peripheral nerve tissue. Keita M, Magy L, Richard L, Piaser M, Vallat JM.

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21 Case Lauv anti-igg

22 NERVE BIOPSY MAY BE STILL VERY USEFUL TECHNIQUES: - Which nerve? - Optic microscopy Immuno - Electron microscopy Immuno RESULTS: - Normal - Lesions: axon myelin interstitial tissue others: toxic, infection

23 N of Ranvier Acute axonal lesions: «ovoids». Segmental demyelination lesions

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26 INTRA-AXONAL MITOCHONDRIA: HUMAN NERVES NORMAL GDAP1 MUTATION (Charcot-Marie)

27 Ultrastructural anomalies of axonal mitochondria: mfn2 mutations

28 GAN: gigaxonin

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31 CX 32 CMTX = CX32 MUTATION

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33 NERVE BIOPSY MAY BE STILL VERY USEFUL TECHNIQUES: - Which nerve? - Optic microscopy Immuno - Electron microscopy Immuno RESULTS: - Normal - Lesions: axon myelin interstitial tissue others: toxic, infection

34 CIDP

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36 mac nucleus axon

37 Longitudinal section Transverse section mac SC A A C mac mac Case 3 Case 1

38 AD CMT dem dup PMP22 (CMT1A) Concentric proliferations of Schwann cells like «onion bulbs»

39 AD CMT dem P0

40 CIDP

41 CIDP

42 Case Flori PMP22 mut and delet

43 CONGENITAL AMYELINATING NEUROPATHY CASE ESSOB 34 WEEKS CONTROL: 1 month

44 AD CMT dem P0 Uncompacted myelin lamellae Normally compacted myelin lamellae

45 Waldenstrom - IgM

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47 IgM IgG IgA

48 MTMR2 MUTATION = CMT4B1: AR CMT dem MTMR2 Numerous out and in-foldings of the myelin lamellae

49 AXON AXON

50 NERVE BIOPSY MAY BE STILL VERY USEFUL TECHNIQUES: - Which nerve? - Optic microscopy Immuno - Electron microscopy Immuno RESULTS: - Normal - Lesions: axon myelin interstitial tissue others: toxic, infection

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52 T cells; CIDP

53 B cells; lymphoma

54 Congo red

55 Anti TTR ab

56 NERVE BIOPSY MAY BE STILL VERY USEFUL TECHNIQUES: - Which nerve? - Optic microscopy Immuno - Electron microscopy Immuno RESULTS: - Normal - Lesions: axon myelin interstitial tissue others: toxic, infection

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63 NERVE BIOPSY CONCLUSION No specific lesion; nevertheless, several may be considered as evocative but need to be correlated with other data. NB is very useful to explain mechanisms of nerve lesions in some conditions such as a polyneuropathy associated to a monoclonal dysglobulinemia and to discuss treatments. Electron microscopy examination is often very helpful;

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65 PCR CLONALITY ON NERVE BIOPSY 16 patients neurolymphomatosis axonal (75%), painful (81%) neuropathy B-cell lymphoma (94%) Primary nervous lymphoma (62,5%) Neuropathological results : Majoritary epineurial perivascular infiltration Axonal loss CD20 + (one CD3+) Clonality results : Monoclonal Oligoclonal No amplification 22 controls with cell infiltrates (CIDP, Vasculitis) 6% 6% 88% Specificity 95,4% Sensitivity 87,5% Great yield of clonality testing on nerve biopsy for the diagnosis of lymphoma Necessary contact between clinician, pathologist and biologist