Histological analysis of the sciatic nerve CG revealed that the nerve fibers were of normal range, with different diameters, and revealed the presence of Schwann cell nuclei at the periphery of the myelin sheath and fibroblast nuclei in the
endoneurium. Perineurium consists of connective tissue modeled; it performed involving the whole nerve, forming concentric layers around the same; fibroblast nuclei were also visualized.
In Grade 3, axonal degeneration and loss of
endoneurium may occur, and nerve fiber continuity recovery may be incomplete.
Inflammatory cell infiltrate, fibrosis of the epineurium, perineurium,
endoneurium, loss of fibres and absence of bacilli were found in all patients.
Sural nerve biopsies from these patients showed increased inflammation involving the epi- and
endoneurium. (1) The pathophysiology of this neuralspecific inflammation is unknown.
Common to all head and neck tumours including skin cancers, nerve sheath spread via the
endoneurium, perineurium or perineural lymphatics requires meticulous attention to the paths of the Vth and VIIth nerves and their branches.
Collagen type III, also known as reticular fiber, is involved in forming the scaffolding for the cells of the loose connective tissues related to the
endoneurium, vascular walls, and smooth muscle.
(7) described abnormal accumulation of mononuclear cells around nerve epineurium and
endoneurium in the absence of vasculitis.
Collagen is present within the onion bulbs, and the
endoneurium contains an abundant mucinous matrix.
Following the presentation of bacterial or viral epitopes by macrophages, T cells become activated and penetrate the
endoneurium, where they engage epitopes on abaxonal Schwann cells, thereby triggering a cytokine cascade [3].
(6) More recently, investigators have proposed that malignant cells invade and spread via potential spaces in the connective tissue planes of the perineurium and
endoneurium without inciting an inflammatory response in the surrounding stroma or invading the nerve fibers themselves.
facial trochlear optic phrenic axon dendrite occipital hypoglossal frontal mandibular nasociliary ophthalmic tibial laryngeal hillock bouton median splanchnic hypogastric femoral genitofemoral plexus pudendal myelin trigeminal abducens oculomotor vagus glossopharyngeal vestibulocochlear accessory auricular maxillary lacrimal supraorbital ethmoidal peroneal
endoneurium synapse ganglion antebrachial acetylcholine ramus iliohypogastric subcostal obturator ilioinguinal oligodendrocyte nerve astrocyte
The
endoneurium contained myelinated nerve fibres with different diameters and thicknesses of their myelin sheaths.