Neuromuscular disorders 2: Peripheral nerve

Back to "Neuropathology for Neurology Residents"

Neuromuscular disorders 2: Peripheral nerve

Last updated on Sunday, July 20 2008 by jdmiles

Related images:

Target fibers: NADH-TR stain
Target fibers are characterized by absent oxidative and ATPase activity, and are felt to be a consequence of re-organization of the muscle cytoplasm upon reinnervation.

Diabetic neuropathy, sural nerve, toluidine blue x200
The nerve demonstrates a marked loss of large and small myelinated fibers, a nonspecific pattern typical of axonal neuropathies.

Diabetic neuropathy,Sural nerve, toluidine bluex600
At high magnification, clusters of thinly myelinated fibers consistent with axonal sprouts can be identified, and signify axonal regeneration consequent to axonal degeneration. Thickening of capillary basement membranes is also apparent.

Hereditary sensory and motor neuropathy, type 1, sural nerve, toluidine blue x 200
Transverse section of the nerve shows loss of myelinated fibers accompanied by nodular schwann cell proliferations

Hereditary sensory and motor neuropathy, type 1, sural nerve, toluidine blue x 400
Redundant Schwann cell proliferations (onion bulbs) can be appreciated.

Hereditary sensory and motor neuropathy, type 1, sural nerve, toluidine blue X 600.
Onion bulb formations are seen uniformly throughout the nerve biopsy. The axons themselves are in various stages of myelination or demyelination.

Necrotizing vasculitis involving epineurial arteriole
The size of the blood vessel involved is typical for involvement of peripheral nerve by systemic vasculitis, such as polyarteritis nodosa, Wegener's granulomatosis, and Churg-Strauss arteritis.

Necrotizing vasculitis involving epineurial blood vessels.
Histopathologic features are consistent with nerve involvement by systemic vasculitis.

Denervation atrophy of skeletal muscle, NADH-TR
Areas devoid of oxidative enzyme activity are seen both in core myopathies and in muscle fiber reinnervation. The latter is encountered in the setting of denervation, in which instances the central cores may demonstrate areas of enhanced oxidative activity...

Leukemic infiltration of peripheral nerve
Among the many ways in which the neuromuscular system may be affected in patient's with hematopoietic malignancies, direct leukemic invasion is among the least common.

Polyglucosan body disease, intramuscular nerve twig, H&E stained x 400
Although rare, small polyglucosan bodies may be encountered in peripheral nerves within normal asymptomatic patients, multiple, large polyglucosan bodies are considered indicative of polyglucosan body disease, a multisystem disorder probably related to type...

Review of the relevant anatomy