Anatomy of diseases of the nervous system

2021-05-13 10:32 AM

Lesions are purulent encephalitis or brain abscess. The most common sites are the temporal lobes and the hemisphere of the cerebellum

The nervous system and its appendages are composed of many basic types of cells or tissues. Although the pathological changes of the nervous system do not differ from each other in the body, they often cause very variable and heterogeneous dysfunctions, depending on the location of the lesion. Heterogeneity of neurological responses depends on many factors, including 4 main factors:

After the skull stops growing, the size of the skull does not change.

The nervous system has only a limited amount of mobile space.

Immobility of the hard meninges

Heterogeneity of structural changes and progression of lesions.

Diseases of the nervous system have many causes such as inflammation, degeneration, damage, birth defects, tumours, ...

Don't come

May be caused by parasites, fungi, bacteria, Rickettsia, viruses ...

Encephalitis caused by parasites and fungi

Due to Toxoplasma, Trichina, larvae of tapeworms, malaria, Actinomycès, Cryptococcus. Lesions occur both in the brain and meninges.

Bacterial encephalitis

Due to staph (most common), streptococci, pneumococcal ... Bacteria enter the brain directly through a wound (trauma, surgery), or spread from nearby places such as in otitis media, or sometimes from a distance (from the bronchi).

Lesions are purulent encephalitis or brain abscess. The most common sites are the temporal lobes and the hemisphere of the cerebellum. These abscesses are necrotic, pus-coated, with a cellular reaction of fatty particles and fibrotic secretions. Surrounding there is congestion, fibrosis and the response of glial tissue. When ruptured abscesses can cause diffuse encephalitis and meningitis.

The specific form of bacterial encephalitis is caused by tuberculosis and syphilis.

Because of the tuberculosis bacteria: TB bacteria travel through the bloodstream to form tuberculosis particles in the meningeal, cerebral cortex and can create tumours called tuberculosis in brain tissue (easily misdiagnosed with real tumours in the brain).

Because syphilis spirochetes: in addition to the damage to the meninges, the syphilis bacteria also cause damage to syphilis in the brain tissue (damage the brain tissue and cause functional disorders such as systemic weakness) or in the spinal cord. posterior root chemistry and posterior part of the spinal cord.

They come not from the virus

It is a very important group of diseases in the clinic.

The damage is diffuse in the brain and sometimes in the spinal cord. Meningitis is often accompanied by encephalitis. Lesions include an inflammatory response similar to an inflammatory response in other organs, but with some distinct characteristics. The damage also varies depending on the type of virus that causes the disease, although it has common features such as congestion, nodular haemorrhage in the peri-vascular spaces, cytoplasmic and cytoplasmic infiltration, along with macrophages around affected cells. injury. The stromal cells behave in the same way as fibrosis. Areas of loss of myelin and focal cerebral flare may appear.

The location and nature of the lesion also have some variations, specific to each virus. For example:

Rabies virus damages the brain, spinal cord and adds Negri inclusions in the nerve ganglion cells of the brain (usually located between the nucleus and the nerve tail).

Poliovirus causes damage to the spinal cord (usually in the anterior horn), the additional damage can be buried in the nucleus of the lymph node.

Encephalitis secondary to infection or vaccination

An acute complication of the cerebrospinal nervous system, rare, occurring during the convalescence of a viral infection (mumps, chickenpox, influenza, measles) or after vaccination (pox, rabies). Disease can occur without a history of illness or vaccinations.

There are many hypotheses about the pathogenesis, but many of Glauzman and Von Bogaret's many theories are supported that the lesion has more than one antigen-antibody properties.

Lesions include congestion, severe oedema of the meninges and brain, lymphoid infiltration, and later there are alternating glial tissue cells around the white matter veins. Can see myelin destruction with necrotic areas that are sometimes quite large.

The patient can die with severe damage to the nerve axes or recover without sequelae.

Meningitis

Spastic meningitis

Most often due to pneumococcal, staphylococcus aureus, streptococci. Bacteria invade from the outside by fracturing the skull (trauma) or spreading from the primary drive of the paranasal sinuses and mastoid bone. In the spinal cord, meningitis can occur after infection of the spine, rarely from a retroperitoneal, or pleural infection.

The damage is in the form of a pus wrap with swelling, congestion, surrounding skull and may spread to one or both sides of the brain.

In addition to the normal form, there are 2 special forms, which are inflammation of the epidermal, hypertrophic periosteal area in the neck that makes the meninges (and sometimes the soft meninges) thicken in the neck in syphilis and (2) meningitis. Hard brain in spinal tuberculosis (Pott's disease) usually in the chest and abdomen.

Soft meningitis

It can be purulent (caused by bacteria or Actinomycès) or non-purulent (caused by tuberculosis, syphilis, fungi).

Meningitis

Due to meningococci, pneumococci, streptococci, staphylococci, gonorrhoea, Actinomycès and rarely due to intestinal bacilli in children. Most importantly, the meninges (which can occur as a fluid) penetrate through the meninges through the upper respiratory tract (nasopharynx) or sometimes through the bloodstream.

Injury: the discharge contains pus, located at the base of the brain, often spread to the meninges of the spinal cord as well as to the choroid and ventricular plexus.

At first brain tissue swelling, congestion accompanied by neutrophil infiltration into small clumps in the soft meninges and neighbouring brain tissue. When the disease is severe, the discharge spreads, containing a lot of white blood cells and white blood cells. With good treatment, the effluent gradually less and contains lymph cells, macrophages, mononuclear cells.

The lower cortex can cause haemorrhage, thrombosis, infarction, if severe it can cause complications due to brain cell necrosis.

Soft, non-purulent meningitis

Meningitis: Usually secondary to the injury elsewhere and is only part of systemic TB.

Oedema of the brain tissue, pale green, mucous, and clear, in the arachnoid space. There are small yellow tuberculosis particles along the subarachnoid blood vessels and above the choroid plexus.

Under a microscope, the same basic damage as TB elsewhere can lead to fibrosis, thickening of the meninges.

 Meningococcal meningitis: Due to a virus that infects people through the urine of infected mice. The disease is usually mild, rarely fatal. Diagnosis is based on the presence of specific neutral antibodies.

There is infiltration of many lymph cells in the arachnoid space, the choroid plexus and in the cerebrospinal fluid.

Fungal meningitis: Due to the fungus Cryptococcus néoformans, penetrates through the respiratory tract.

In about 50% of cases, there is damage to the brain.

There is very little cellular response in brain tissue. The fungi are in mucus and polysaccharide wraps. Rarely there is a granulomatous lesion.

Nervous system tumours

In nervous system tumours, intracranial tumours play a major and much more important role than extracranial tumours because of their effects on the central nervous system and patient health. Intracranial tumours originate from brain tissue (neurons, glial tissue, blood vessels in the brain), from extra brain tissue (such as meninges, cranial nerves, lobe-brain glands). In addition, there are secondary brain tumours caused by cancer elsewhere that have spread to the brain.

Malignant brain tumours usually do not allow distant metastasis, but only penetrate locally and spread to nearby tissue.

There are many types of tumours that heal morphologically but can lead to premature death because the tumour is in a location that is difficult to reach (for example, IVF 4) and some tumours (e.g., tumours invasive astrocytes) spread far beyond the surrounding tissue, making it impossible to completely remove it. Even when it is possible to try to remove these tumours, at times it is necessary to sacrifice a lot of brain tissue, depriving the patient of functioning.

Many tumours can rupture into the meninges and ventricles, spreading cells according to the cerebrospinal fluid, forming a way to spread cancer in the nerve tissue, creating cancer spreading nests in the brain, spinal cord, and roots. neurological and clinical manifestations in the form of meningitis due to cancer.

Extrinsic metastases of intracranial tumours are very rare, if present, are usually glioblastoma and myeloblastoma. Surgery such as ventricular-peritoneal bypass surgery, surgery to tear the sclera and subarachnoid space, can cause metastasis outside the nervous system.

Clinically, tumours of the nervous system can cause symptoms and signs that vary widely, depending on the location, level of growth and penetration of the tumour. Intracranial tumours alone, like other lesions that take up space in the skull, can cause local and systemic effects.

The local effects of the tumour depend on the size and location of the tumour, including hemiplegia, strokes, ataxia, or weakness, but these symptoms are also present in other diseases.

The systemic effect of the tumour is due to increased intracranial pressure. In particular, tumours in quiet areas such as the frontal lobe, can initiate very vague and grow to a large size, before it can cause local and systemic effects enough to make the patient walk. medical examination. This is a distinctive feature of brain cancers due to metastasis (often there is oedema around metastatic foci that easily cause obvious symptoms).

According to many non-selective surveys, brain tumours have an incidence of about 1.2% of all autopsies and about 9.2% of all primary tumours.

It is one of the most common types of tumours in children, becoming rarer in young people, more common in the elderly, and becoming less common in people over 70 years of age. Depending on the age, there is the dominant type of tumour. For example, myeloblastoma is predominantly found in children and young people. In children, 70% of intracranial tumours are under the tent. In adults, by contrast, 70% of intracranial tumours are upper tent tumours.

According to the World Health Organization, the incidence of brain tumours in adults is as follows:

Secondary brain tumour 25-30%.

Primary brain tumour 70-75%.

Glial tumours 40-45%.

Neuroblastoma 25-30%.

Star cell tumours 8-12%.

Endothelial tumour 2-3%.

Dendritic cell tumours 2-3%.

Myeloblastoma 2-3%.

Meningeal tumor12-15%.

Tumours of the auditory nerve 5-10%.

The tumour is derived from glial tissue

Collectively referred to as gliomas, which originate from epithelial stromal cells and include astrocytoma, multiple glioblastomata, dendritic cell tumours, and endothelial tumours.

Stellar cell tumours

Stellar cell tumours range from well-distinguished to very degenerative types. The highly differentiated type has a histological pattern that is very similar to the normal stellar response. The degenerative type belongs to the group of glioblastomata.

The incidence of astrocytes is 20-30% of glioma, if not including glioblastoma and 80-90% if glioblastoma is included.

The highest incidence of the disease is in children, the male / female ratio is 2/1. There is a clear correlation between the age of disease with the type of tissue and the location of the tumour. In children and young people, the most common type is a hairy stellar cell tumour in the cerebellum, hypothalamus, 3 ventricles, where the two optic nerve and brain intersect. In adults, most astrocytes are present in the cerebral hemisphere and rarely degenerate. With the exception of the cerebellar hair-type astrocytes and the optic nerve that proceeds like a hamartoma (treatable by resection), all astrocytes at any location, at differentiation all have rapid progression and bad prognosis.

General:

Clearly differentiated tumours are usually invasive lesions with unknown limits, gray-white colour, like flesh. This damage enlarges and distorts nearby brain tissue. Tumours can be small, several centimetres in diameter, or very large, occupy most of the cerebral hemisphere, sometimes spread to the other hemisphere. The tumour is usually dense, sometimes small, can be hard or soft and gelatin-like (depending on the type).

 Micro:

Based on the morphology of tumour cells, people distinguish four types:

Silk cell tumours.

Hair-type astrocytes.

Protozoa of astrocytes.

Blistering stellar cell tumours.

However, in order to be easily associated with clinical, serving treatment and monitoring disease progression, stellar cell tumours are often classified into 4 degrees with increasing malignancy:

Grade 1 stellar cell tumours: A highly differentiated type, usually in the form of a hairy, sometimes filamentous, protozoan, or bulging type. Tumour cells are usually very similar to normal astrocytes, although they have marked hyperplasia, no division, and no haemorrhage. Tumours progress slowly, are sensitive to radiation therapy.

Grade 2 stellar cell tumours: U often have many necrotic and haemorrhagic foci, and many small capsules, sometimes calcified. The tumour structure consists of many small cells, triangular or polyhedron, with many cytoplasmic branches attached to the vascular wall, can create a pattern of false roses around the vessel. The blood vessels also have hyperplasia. Tumours can also be silk-like, protozoa and bulging.

Grade 3 and 4 stellar cell tumours: Kernohan called these 2 types under a common name glioblastoma with the highest degree of diversity, accounting for 50% of glial tumours. Tumours have many colours due to many haemorrhagic, necrotic and small cysts.

The tumour structure has two characteristics: cells are very rich, spindle-shaped or round, swollen, with a nucleus, an atypical nucleus, sometimes with multiple nuclei (like cytoplasm), and multiple blood vessels. strong production with thrombosis with necrotic foci, periascular fibroblasts increase.

The tumour is very malignant, rapidly progressing, spreading to the soft meningeal region, penetrating the subarachnoid, ventricular space, distant metastasis to the lymph node, lung, kidney.

Another type of astrocytoma that is common in about 20 to 30 years of age is glioma, in which a large area of ​​brain tissue or sometimes all of the brain tissue is invaded by neovoltaic cells.

Dendritic cell tumours

Accounting for 5% of intracranial gliomas. Age from 30-50 years old, men and women are equally affected. In the cerebral hemisphere, the white matter region is rare in the gray matter. Possible in the spinal cord and cerebellum.

Tumour has a clear boundary, pink-grey in colour, has many calcifications of calcium (can be seen on x-rays), can be encapsulated.

The structure is rich in cells, less stroma. The tumour cell has a small nucleus, is dark stained and is coated with a bright ring of cytoplasm.

In addition, there are 2 different types of u:

Mixed form of dendritic cell tumours and astrocytoma. If the stellar cell composition is degraded, the prognosis is the same as that of a degenerative astrocytoma.

Less branched leukoblastoma: very malignant, with very diverse cells, many mitochondria.

Most dendritic cell tumours progress slowly and cause only localized symptoms. Seizures, for example. These symptoms may return after many years (5 to 20 years). On the other hand, in some cases the tumour progresses quickly. It should be noted that there is no correlation between the microscopic morphology and the biology of the tumour.

The tumour is also easy to recur, can spread to the subarachnoid space, penetrate the soft meninges, spread along the cerebrospinal fluid. U has a good prognosis when there are many calcifications of calcium.

The tumour can be treated with surgery followed by radiotherapy with an average survival time of 5 years although the prognosis is difficult to predict. May use more chemotherapy.

Endothelial tumour

Tumour cells originate from cells lining the interior of the ventricles and spinal canal.

U can be of any age but most commonly in children and young adults.

Tumours have incidence of 5-6% of tumours of the intracranial glial tissue, and 63% of tumours of glial tissue in the spinal cord. In the spinal cord, the tumour is usually found in the sacred dorsal area and the horsetail region. Particularly the type of endothelial tumour type papillae-mucus often found in the terminal cord.

In the brain, the tumour is usually in the 4th ventricle (the lower tent), in the third and later ventricles. The tumour has a well-defined boundary, sometimes as a wrap, gray or reddish-brown, papillae.

The structure consists of cells derived from cells lining the inner surface of the ventricles, having a very complex morphology, having many forms:

Choroid plexus: The structure is very similar to the normal choroid plexus, but the cells are taller and the cytoplasm has many cavities containing mucus.

Sometimes the tumour has a degenerative, invasive, and rapidly growing cell called a choroid carcinoma.

Tumour says that while is like-sealing: close on cells and tissue is not mucus existing telephone buffer was dancing.

The endothelial tumour is epithelial.

Endothelial tumour cell form: Very rich in cells, where the cells are arranged in the shape of fake roses.

All 4 types are rare, develop slowly, develop slowly, but can clog cerebrospinal fluid, increasing acute intracranial pressure.

A very malignant, undifferentiated form of myeloma is glia.

Another very benign, mucous tumour of the third ventricle is also sometimes considered to be a form of myeloma.

The main treatment is to remove the tumour. Postoperative radiotherapy is used for malignancy.

Tumours are derived from neurons

Includes neuroblastoma, lymphoma and glioma of the nerve ganglion. 

Neuroblastoma and adult neuronal tumours may be present in the central nervous system, especially on both sides of the cerebral hemisphere, but are more common in the peripheral lymph nodes. and adrenal medulla.

In very rare cases, these tumours can be found in the mediastinum, and are considered to have a teratoma-like origin.

Neuroblastoma of the brain

Malignant, rare. The patient is a child under 10 years old.

Located in the cerebral hemisphere, the frontal lobe has a slightly higher rate than other lobes, sometimes in the cerebellum, has a clear boundary, sclerosis, a gray section, many necrosis, haemorrhage, regression upholstery.

The structure consists of round or oval cells, cytoplasmic boundaries, nucleus, dividing nucleus. The cells gather in clusters, rafts, chains or form fake roses, many connective stromata.

Tumours originate from neuroblastoma, develop rapidly, easily recur after surgery, soon spread and metastasize. 40% of tumours spread by cerebrospinal fluid. Rarely for extracerebral metastases. Unlike tumours in the adrenal medulla, tumours of the brain do not secrete catecholamines.

Prognosis is difficult to predict. The type with differentiated microscopic morphology has a better prognosis.

Treatment of the tumour with surgery, radiotherapy to all brain tissue and chemotherapy.

In addition to the location in the brain, neuroblastoma can also be found in the posterior mediastinum, in the retroperitoneal region. The pathological properties of this type are similar to those found in the brain.

Also derived from neuroblastoma but the retina of children's eye is retinoblastoma, a malignant tumour of a family nature.

Nerve and glioma of the nerve ganglion

These include tumours originating from mature neurons in the peripheral nervous system, the adrenal medulla, and more rarely in the central nervous system.

If the tumour is peripheral, the tumour's stroma originates from flattened Schwann cells, in which a calcium bridge can be seen, the tumour is called a neuronal lymphoma or a lymphoma.

If the tumour is in the central nervous system, with glial tissue being glial tissue, the tumour is called glioma of the nerve ganglion. This type is very rare, usually only found in children and young people.

General:

Tumour is in lump form, clearly limited, with a granular cross-section with small calcification and calcification spots. Typically, the tumour is in 3 ventricular floors, hypothalamus, frontal lobe.

Micro:

Composed of a mixture of 2 nerve and glial components, like a hamartoma. In rare cases, the tumour has an intermediate component like degenerative astrocytes or neuroblastoma, then the tumour invades the surrounding brain tissue, grows rapidly, malignant.

In general, the tumour has a good prognosis and depends on the location and histology. Treatment with resection

Myeloblastoma

Malignant tumours, which originate from residual canal cells, are therefore considered by many authors to regard tumours from primitive or undifferentiated cells.

Tumours are one of the common tumours in the central nervous system of children, with an incidence of 25% of intracranial tumours, ranking second after stellar cell tumours. However, cysts can also be present in adults up to the age of 60 years. Men often get the disease more often than women.

Usually, in the midline of the cerebellum of children, the boundary is quite clear, uncoated, soft, light gray with many necrotic foci, haemorrhage, can spread along the ventricles and meninges. Sometimes the cyst is present in the hemisphere of the cerebrum (adults).

The structure consists of small, monomorphic, spindle-shaped, cytoplasmic cells are unknown. These cells line up in clumps or form a fake rose pattern. U is sensitive to radiation even temporarily.

A special form, called fibroblastoma, has fibrous properties, is found in adults and has a better prognosis. Tumours grow slowly in place.

Tumour of the meninges

Derived from any component of the meninges: arachnoid cells, fibroblasts, blood vessels. Most tumours originate from arachnoid cells in the arachnoid villi. Therefore, the tumour is often found in places where there are many arachnoid villi.

In general, the cyst is slow, benign. On autopsy, especially in people over 70 years old, people often experience small tumours that do not cause symptoms. Symptomatic tumours account for only about 14% of intracranial tumours. Tumours can be present at any age, but most often in middle age, especially women.

Healed meningitis

Accounting for 14% of primary intracranial tumours and 25% of tumours in the spinal cord.

Age from 20 to 60 years old, most often 40 years old.

Location:

In the middle 1/3 of the arch of the cerebral hemisphere, along the sinus veins, the cerebral sickle area, the olfactory region, the small branches of the butterfly bone, around the occipital, the eye socket.

Tumours have a clear boundary, often stick to the sclera, pinch the brain tissue but do not penetrate. U is yellowish-white or reddish-white, the section has many fibres, often with high, sandy particles. The tumour is usually solitary, though sometimes multiple, as seen in von Recklinghausen's disease, or in diffuse meningitis.

Cytoplasmic form: most commonly seen.

The structure consists of cells derived from the arachnoid membrane, which have many forms depending on the cell morphology:

The fibrous form, also known as fibroblast meningioma, is also common.

Sand form: also, commonly seen, characterized by calcium deposits forming calcium spheres called sandy bodies.

A type of blood vessel called a meningioma: a structure characterized by many microvasculature. This form is widespread, easy to recurrence, the worst prognosis of the above types.

Cyanocyte type: very rare.

Most meningeal tumours are benign. Infiltration into the adjacent skull, if present, is also not accompanied by spread, metastasis or infiltration into surrounding brain tissue. The distinction between these five microscopic forms has very little clinical value.

The prognosis depends on the location of the tumour and on the ability of the tumour to be cut (most can be cut). The recurrence rate 5 years after surgery is about 15%.

Malignant meningitis

Account for 2% of primary intracranial tumours.

Patients are children, rarely adolescents.

Tumours of blood vessels and perivascular structure

Including tumours whose structure and properties are the same as elsewhere in the body such as:

Vascular tumours (benign): usually on the surface of the cerebrum.

Vascular fibroblasts or vascular endothelial tumours: most commonly in the adult cerebellum.

Sarcomas such as fibrosarcoma, spindle sarcoma, sarcoma multiforme.

Lymphoma.

Other types of central nervous system tumours

Tumours of the epidermis.

Tumour sheathed envelope

Malignant tumours

Spinal tumours: are malignant tumours, rare, accounting for 1% of intracranial tumours. Patients over 40 years old, usually men. The tumour is usually in the region of the coccyx (50% of cases), the base of the skull (the butterfly, the pituitary: 30% of the cases), the vertebrae and the back (10%), rarely in places such as the maxilla, pharynx. ... Tumours small, or large (in the apex), clearly defined, pinched or stuck to the bone, solid or mucus-coated form. The basic structure is large polygonal cells or clustered in lobules or arrays within the mucous stroma. The cytoplasm and nucleus both contain mucus, so the cells have a special shape called the bladder. Rarely have fibroblast-like spindle cells. U is inverse embryonic nature, originates from the residual spinal tissue in the bone, grows slowly, penetrates in place, easy to recurrence. Tumours in the amputated region can spread to the lung, soft tissue, and liver metastasis. Tumours are sensitive to radiation therapy.

Skull-throat tumours: Account for 3% of intracranial tumours, of the malignant borderline. Patients are young children and adolescents (50% of cases). Tumours round or oval, several cm in diameter in pituitary pit, pituitary anterior pituitary, well-demarcated, thin sheath, gray or reddish-brown cross-section or containing light brown fluid and calcification, ossification regions. The structure consists of rafts, clusters, cell-like epithelial cells with keratinocytes. The central cells can degenerate into mucous tissue or a sheath lined with the spiny epithelium. Buffer tissue has many calcifications of calcium, bone chemistry, cholesterol crystals, and inflammatory tissue. This structure resembles an enamel-forming fibroblastoma of the jaw bone, so it is also called pituitary enamel tumour. Tumours of inverse origin, formed from the residual tissue of the Rathke sac. Tumours invade nearby tissue, compression of the pituitary gland, the visual interference area atrophy of the optic nerve, destroying the sclera, the butterfly bone, the brain, easily recurring, rare metastases. Many authors consider this to be a type of tumour of the pituitary gland.

Cancer has spread to the brain

According to Robbins, metastasis of cancer from elsewhere to the brain accounts for 20-25% of intracranial tumours. With the exception of basal cell carcinomas of the skin, all cancers have the potential to spread to the brain, especially those of the bronchi and breast.

Other cancers that often spread to the brain are carcinomas of the kidneys, gastrointestinal tract, and malignancies.

Usually, brain metastases appear when cancer has spread elsewhere. Rarely, these metastatic foci manifest themselves as a primary brain tumour.

Particularly, facial skin cancer (basal cell carcinoma) can spread into the eye socket and enter the brain.

Lesions usually have multiple foci in the cerebral hemisphere (usually in the boundaries of gray matter and white matter), cerebellum, brain stem, meninges. These foci are in the form of a lump, firm, 1 cm to several cm in size, quite well-defined, sometimes with necrosis or haemorrhage.

The microscopic structure of the metastatic foci is similar to that of primary cancer.

In practice, it is often difficult to identify the primary drive without a clear indication of the primary drive.

Nerve tumours

Most tumours are outside the skull and spinal cord, so they are also called peripheral nerve tumours. Rarely, there is a tumour in the skull such as a tumour of the VIII cranial nerve.

Nerve fibres

Benign tumours, derived from components of the nerve. Available at any age.

Tumours can be in many places on the body such as the back, limbs, shoulders, rarely found in the mediastinum, upper respiratory tract, gastrointestinal tract, salivary glands. Tumours often have hyperplasia, rarely solitary form, but often have many lumps (sometimes up to hundreds, thousands of small tumours). When there are multiple lumps is called neurofibroma or von Recklinghausen's disease).

The tumour is usually sheath, round or oval, soft, forming a large bulge on the nerve.

The structure includes endothelial hyperplasia associated with Schwann cell hyperplasia. Schwann cells are arranged parallel to each other in long bundles and in connective tissue oedema or fibrosis with fibroblasts and also dark cells. Occasionally scattered circular Meissner-like structures and nerve fibres with or without myelin sheath.

Tumours progress slowly. About 10% of large neural fibroma tumours can turn malignant, becoming malignant Schwann envelopes or nerve fibre sarcomas.

Schwann sheath tumours (Schwann cell tumours, nerve sheath tumours)

Tumour heals. Patients are usually women between the ages of 40 and 60 years.

Tumours can be in cranial nerves (most cranial nerve VIII), intercostal nerves, peripheral nerves, subcutaneous tissue, eye mucosa, mouth, upper respiratory tract, in organs (stomach, intestine), posterior mediastinum. Sometimes, in bone, the tumour originates from nerve fibres of the periosteum.

Tumours have a clear shell, round, rarely larger than 8 cm, soft, chewy density, gray-white cross-section, with many foci of mucous degeneration, haemorrhage, many small capsules.

The structure consists of clusters of long spindle-shaped Schwann cells, with a small flat nucleus, with few cytoplasms. Tumour cells can be arranged in 2 types:

Antoni A: very rich cells meeting in twisted bundles, either arranged parallel (like a fence) or curled up into Verocay bodies interspersed with rich sag lattice.

Antoni B: few cells in a thin web of filaments, with mucous degenerative stroma and inner degeneration with small bundles.

Tumour Schwann can be solitary or multiple (von Recklinghausen's disease), progressing slowly, with little recurrence, and malignancy rare.

Neurofibroma (von Recklinghausen's disease)

A rare, malignant thyroid type, including multiple neural fibroids, Schwann-covered tumours with changes in many areas of the body. There are usually coffee-milk hyperplasia spots on the skin.

Based on the clinical and anatomical differences of the disease, it can be divided into 3 types:

The peripheral form, also known as the skin form, manifests itself as multiple fibroids under the skin, in the periphery with changes in the skin.

The central form manifests itself as intracranial tumours, spinal cord tumours, cranial nerve tumours and spinal cord neuromas.

The visceral form is often associated with tumours of the organ, originating from the nerve crest such as chromosome, adrenal lymphoma, peripheral neuroblastoma.

The disease can turn malignant into nerve fibre sarcoma or malignant Schwann sheath.

Tumour cover the evil Schwann

The structure is similar to benign tumours but is rich in cells, hyperchromic kernels can be confused with fibrosarcomas or smooth muscle sarcomas.

Tumours grow rapidly, penetrate nearby tissue, metastasize in the bloodstream.

Nerve fibre sarcomas

The structure is diverse with many spindle cells arranged in bunches, sometimes like fibrosarcoma, many atypical cells, hyperchromic nuclei, with multicellular macrophages, astrocytes.

Tumours are fast-growing, infiltrate locally, rarely distant metastases.