Intracranial metastases

Introduction to intracranial metastases Intracranial Metastatic Tumors are metastatic to other intracranial malignant tumors. Carcinoma, sarcoma and melanoma can be transferred to the cranium. Most of the intracranial metastases seen in the clinic are cancer metastasis, accounting for 90%. %the above. There are three ways for malignant tumors to metastasize to the brain: 1 through the bloodstream; 2 through the lymph; 3 direct invasion. Among them, menstrual blood flow is the most common route, and the metastasis route and metastasis site are related to the site of the primary tumor. Such as lung cancer, breast cancer, skin cancer and other major blood flow transfer, easy to form multiple metastatic cancer in the brain, no treatment more quickly died. Gastrointestinal cancers are more likely to metastasize through the lymphatic system and spread to the meninges. basic knowledge The proportion of illness: 0.02% Susceptible people: no special people Mode of infection: non-infectious Complications: cerebral edema, nystagmus, ataxia

Intracranial metastases

(1) Causes of the disease

In males, lung cancer is the most common. In women, breast cancer is the most common. Except for lung and breast (female), the organs and parts of the more common primary lesions have digestive tract, urinary tract and uterus. Ovarian, skin, prostate, thyroid, bones, etc., metastases are mainly located in the brain, a few are found in the skull and meninges, and the meningeal metastasis is mostly diffuse distribution on the inner surface of the dura mater and the pia mater.

In recent years, the molecular biological mechanism of tumor metastasis has been very active. Tumor metastasis is composed of a series of complex biological events, which are mainly through the following processes: 1 gene activation, amplification, deletion or inhibition of gene inactivation; 2 neovascularization; 3 cells malignant proliferation; 4 evade host immune attack; 5 tolerant drug treatment; 6 tumor expression and activation of metastasis-related genes and invasion; 7 tumor cells through the adhesion molecules, protease activity changes and cell movement to achieve secretion growth at the metastatic site, blood vessels Generating factors and cloning growth, it has been found that the ability of tumor cells to invade and metastasize is mainly related to abnormal "social" function of cells, and has no obvious relationship with abnormal "housekeeping" function of cells. The abnormality of "social" function of cells is mainly caused by The abnormalities of glycosylation of various glycoprotein molecules involved in the function of cell surface include many types, in which the formation of cell-surface N-linked sugar chains 1,6 branch antennas is the most common, and a large number of studies have confirmed that The invasion behavior of tumor cells is largely due to the formation of excessive 1,6 on the cell surface. Branching, which in turn produces a multi-antenna N-glycan structure, changes the biological shape of the glycoprotein molecule, causes abnormalities in the adhesion function of tumor cells, and increases the metastatic potential of tumor cells.

(two) pathogenesis

Hematogenous dissemination and direct infiltration are the two major intracranial metastases, with lymphatic metastasis and cerebrospinal fluid metastases being less common.

1. Direct infiltration: peripheral and adjacent organs of the skull, tissues, such as the eyes, ears, nasopharynx, paranasal sinus, head surface, soft tissue of the neck, etc. are the predilection sites of primary and secondary tumors, common with nasopharyngeal carcinoma, Retinoblastoma, jugular bulbar tumor, they can directly invade the skull, dura mater, or the transcranial base pores to the essence of the outer surface of the brain, around the nerves and blood vessels in the skull base pores, loose structure, easy to invade tumor cells Some pores not only have their periosteum and dura mater, but also communicate with the subarachnoid space, such as the eye and eyelids. After the tumor cells invade the brain, or spread in the subarachnoid space with the cerebrospinal fluid, or deep into the brain. The perivascular space invades the brain parenchyma.

2. Blood transfer: Most tumor cells transfer to the brain through the blood pathway, most of which pass through the arterial system. A few tumors can be transferred to the brain through the vertebral venous system. After the primary tumor grows to a certain volume, the neovascularization grows. Tumor cells infiltrate small blood vessels, mostly veins, and return to the heart with blood, and then spread to the brain through the carotid artery and vertebral artery system. The common primary tumor of blood metastasis is lung cancer (12.66%), breast cancer (16.96). %), chorionic epithelial carcinoma (8%), melanoma (7.98%), digestive tract cancer (7.68%), kidney cancer (7.66%), others (12%) and unidentified (12.06%), due to our breast The incidence of cancer and prostate cancer is lower than that in Western countries, and the incidence of choriocarcinoma is higher than that in Western countries. Therefore, in China's intracranial metastases, chorionic epithelial cancer is second only to lung cancer, and sarcoma brain metastasis is rare. Only 7%, which is related to the incidence of sarcoma and cancer is 1:10. In lymphatic hematopoietic tumors, leukemia is more common, and its intracranial metastasis rate is similar to lung cancer.

3. Cerebrospinal fluid metastasis and lymphatic metastasis: some brain and spinal cord tumors, especially ependymoma and poorly differentiated glioma, can be planted along the subarachnoid space, often after tumor resection or biopsy Malignant tumors in the periphery and adjacent parts of the skull can enter the cerebrospinal fluid or vertebral venous plexus through the lymphatic space around the cranial cavity, and further intracranial metastasis occurs.

4. The site of the metastasis

(1) Brain parenchyma: Most of the metastasis occurs in the blood supply area of the middle cerebral artery. This is because the internal carotid artery is thicker than the vertebral artery, and the middle cerebral artery is a natural continuation of the internal carotid artery. More abundant, the most common metastatic site is the frontal lobe, followed by the parietal lobe, the occipital lobe, which can involve more than 2 brain lobe at the same time, and can even affect the bilateral cerebral hemisphere. These metastases are common at the junction of cortex and white matter. This is because the blood supply to the cerebral cortex is 3 to 4 times that of the subcortical white matter. Therefore, on the anatomical structure, the blood supply artery is suddenly thinned at the cortex-white matter junction, and the metastatic tumor thrombus is mostly blocked and easily transferred here. , growth, clinically common from the lungs, uterus and other parts, others can also be transferred to the thalamus, most of the transvertebral-basal artery system transfer in the cerebellar hemisphere, but also to the brain stem.

(2) pia mater and arachnoid: common in acute leukemia, non-Hodgkin's lymphoma, breast cancer, etc., basal pool, lateral fissure pool is most often involved, showing arachnoid thickening, grayish white opaque, a bit Bleeding and tumor nodules are scattered, and tumor cell deposits are also seen on the choroid plexus and ventricular wall of the brain.

(3) Dura mater: common in prostate cancer, breast cancer, malignant lymphoma, melanoma, etc., because the dura mater is anatomically adjacent to the skull, there is often a corresponding transfer of the skull, which may have hyperplasia or destruction, when the dura mater Metastasis involving large venous sinuses or cranial nerves can cause obvious clinical symptoms and is a common type of metastatic tumor in children.

5. Pathological types of primary tumors Understanding the different pathological types of primary tumors is important for guiding radiotherapy and chemotherapy. Adenocarcinoma is the most common pathological type of primary disease. This is because lung cancer accounts for the first place in intracranial metastases. Among them, adenocarcinoma is the most metastatic; of course, the type of adenocarcinoma in the digestive tract can also be transferred to the cranium. Other common types are squamous cell carcinoma, undifferentiated carcinoma, papillary carcinoma, sarcoma and the like.

6. Pathological features and types of metastatic tumors Most of the brain metastases are multiple and multi-nodular. Harr and other autopsy reports account for 75% of the cases, but this is not the case in clinical practice. A small lesion was examined, and because of its small size and no clinical manifestation, some patients were not treated. According to their pathological features, they can be divided into the following two categories:

(1) Nodular type: This is the most common type. The size of the lesions varies greatly. The larger ones can reach more than 10cm in diameter. The small ones are often invisible to the naked eye, and can be divided into single and multiple hairs. The cells are divided into different or different arterial systems and enter the brain at the same time. The tumor is often spherical and has a clear boundary. It grows at the junction of white matter and cortex, and then grows gradually. The inward white matter grows, and the outer membrane can invade the dura mater. The speed is often faster. If it is accompanied by bleeding or cystic changes, the clinical symptoms are obvious, the tumor texture is soft and hard, the blood supply is not rich, it can be purple, it can be grayish yellow or grayish red, and the tumor is small. Often it is solid. If it grows up and grows quickly, there is a central part of the cystic change or even hemorrhage. The cyst contains yellow, reddish or brown liquid, and the individual is purulent. The edema around the tumor makes the boundary relatively clear, and the degree of edema It can be related to the type of tumor, the number and permeability of tumor blood vessels, local metabolism and the liquid secreted by tumor cells, and also the mechanism of tumor metastasis, the specificity of arterial blood supply and the venous solution of the brain. The specificity of the section is related, but the edema has no obvious relationship with the degree of malignancy of the tumor. The boundary between the tumor tissues under the microscope is unclear. The nest of the tumor cells often infiltrates along the outer membrane of the blood vessels and the brain tissue, and the surrounding tissue is edema, softened and glued. Hyperplasia, its tissue characteristics are consistent with the characteristics of the primary tumor. Obviously, the primary tumor can be inferred to guide the clinical search for the primary lesion for treatment, but the primary lesion is not clear in the lower degree of differentiation. Often mixed with clinical glioma features, if adenoma-like or papillary structures may be misdiagnosed as ependymoma, but metastatic tumors have their own inherent characteristics, such as cancer cells often scattered in normal nerve cells, inflammation In the background of focal or coagulative necrosis, the boundary is clear, the nuclear enlargement is heteromorphic, the ratio of nucleoplasm is increased, the nuclear membrane is obvious, the nucleolus is enlarged, the chromatin is reticulated, and vacuoles are also present in the cytoplasm.

(2) diffuse type: less common, can exist alone or with nodular type, often caused by systemic diseases, manifested as extensive planting of the meninges, involving the pia mater, arachnoid, making it generally thick grayish white , opaque, sometimes a little bit of bleeding and tumor nodules scattered, under the microscope can be seen on the dura mater cell infiltration.

Intracranial metastases prevention

Pay attention to food hygiene, avoid benzopyrene, nitrosamines and other carcinogens into the body, pay attention to personal hygiene, exercise the body, enhance resistance, prevent viral infection, avoid brain trauma, and should be cured in time when brain trauma occurs, already suffering from intracranial People with tumors should not give birth any more. In daily life, they should eat more yellow-green vegetables and fruits, such as carrots, pumpkins, tomatoes, lettuce, cabbage, spinach, jujube, bananas, apples, and mangoes.

Intracranial metastases complications Complications, cerebral edema, nystagmus, ataxia

If surgery is performed, the following complications may occur:

1. Intracranial hemorrhage or hematoma

It is not related to intraoperative hemostasis. With the application of surgical microscope and the improvement of surgical techniques, this complication has been less frequent. The wound is carefully hemostasis and repeated flushing before closing the skull can reduce or avoid postoperative intracranial hemorrhage.

2. Brain edema and postoperative high intracranial pressure

Dehydration drugs can be used to reduce intracranial pressure, and glucocorticoids can alleviate cerebral edema. For tumors with a wide range of lesions or high degree of malignancy, the tumors and non-functional areas of the brain tissue can be removed as much as possible, and the external decompression of the bone flap can be performed.

3. Loss of nerve function

It is related to the important functional area and important structure of intraoperative injury, avoiding injury as much as possible during operation, symptomatic treatment after emergence, due to the serious damage of the tumor to the brain, and often multiple, local symptoms are more significant, and the scope of involvement is wider. Tumors have corresponding signs, more than 40% of patients have hemiplegia, about 15% have unilateral sensory disturbances, about 10% have aphasia, 5% are hemian, and those with cerebellum have nystagmus, ataxia, etc. There may be symptoms of the posterior cranial nerve.

Intracranial metastases Symptoms Common symptoms Loss of weight, slow response, sensory disturbance, weakness, expression, apathy, nausea, dementia, dizziness, diffuse headache, aggressive behavior

Clinical manifestation

1. Onset: acute onset accounts for 40% to 60%, the first symptoms are epilepsy (12% to 20%), stroke (10%), subarachnoid hemorrhage (1%), paresthesia (10%) ), language barrier (1%), oculomotor nerve paralysis (2%) and dance-like hand and foot Xu movement, urine collapse, dizziness, etc., chronic progressive onset accounted for 50% to 60%, the first symptom is headache (23% ~ 60%), mental disorder (9% to 50%).

2. Course of disease: acute progress accounted for about 46.6%, often with moderate onset, rapid coma and hemiplegia within 1 to 2 days, the disease progresses worse, the course of disease is generally less than 2 weeks, more common in chorionic epithelial cancer, melanoma brain metastasis Hemorrhage, multiple brain metastases, cancer embolism or acute cerebral vascular compression and metastases are located in important functional areas, and the intermediate remission period accounts for about 21.4%, that is, after a period of remission in acute onset, intracranial massaging symptoms again Appearance and progressive exacerbation may be due to the gradual reduction of vasomotor dysfunction or hemorrhagic absorption after acute onset of cancer, and the clinical manifestation is gradually relieved. Later, due to the increase in tumor volume and accompanying cerebral edema, the symptoms are aggravated again. The period is usually from 1 week to several weeks, and individual can last for 4 or 8 years. A small number of patients can present TIA-like episodes, which lasts for several weeks or months, and the progressive exacerbation accounts for about 32%, which is characterized by acute onset or chronic onset. The disease is progressively aggravated and lasts for 3 to 4 months.

The clinical manifestations of brain metastases are similar to other intracranial space-occupying lesions, which can be summarized as: 1 symptoms of elevated intracranial pressure; 2 focal symptoms and signs; 3 psychiatric symptoms; 4 meningeal irritation, clinical manifestations of metastases The time of occurrence, the location of the lesion, the number and other factors are different. Some patients may have symptoms of brain metastases at the same time as the primary tumor is found, but it is common that the symptoms of brain metastases are later than the primary tumor.

(1) Increased intracranial pressure: headache is the most common symptom, and it is also an early symptom of most patients. It often occurs in the morning and begins to be a localized headache. It is mostly located on the side of the lesion (related to brain metastases involving the dura mater) Later, it developed into diffuse headache (related to cerebral edema and tumor toxicity). At this time, the headache was severe and persistent, accompanied by nausea and vomiting. In the late stage of the disease, when the patient presented with cachexia, the headache was relieved, due to brain metastases. Increased intracranial pressure develops rapidly, so headache and accompanying intellectual changes, meningeal irritation is obvious, and optic disc edema, intracranial hypertension changes are not obvious.

(2) Common signs: According to the location of the brain metastases and the number of lesions, different signs may appear, such as hemiplegia, partial sensory disturbance, aphasia, cranial nerve palsy, cerebellar signs, meningeal irritation, optic disc edema, etc. The appearance of signs and symptoms is not synchronized, often the former is later than the latter, most of the positioning signs appear in the days to weeks after the occurrence of headache and other symptoms of cranial hypertension. The incidence of contralateral limb weakness is second only to headache. 2 digits.

(3) Psychiatric symptoms: seen in 1/5 ~ 2 / 3 patients, especially in the frontal lobe and meningeal diffuse metastasis, can be the first symptom, manifested as Coca-Saf syndrome, dementia, aggressive behavior.

(4) meningeal irritation: more common in patients with diffuse brain metastases, especially meningeal metastasis and ependymal metastases, sometimes meningeal irritation due to metastatic hemorrhage or inflammatory reaction.

(5) epilepsy: all kinds of seizures can occur, seen in about 40% of patients, with comprehensive tonic-clonic seizures and focal epilepsy more common, early epileptic seizures have localized significance, such as focal Exercise-induced epilepsy often indicates that the lesion is located in the motor area. Focal sensory seizures suggest that the lesion involves the sensory area. Focal epilepsy can occur continuously. As the disease progresses, some patients show generalized tonic-clonic seizures, limb weakness, multiple brain metastases. It is prone to seizures, but there are different opinions on whether the multiple lesions can be inferred based on multiple forms of seizures.

(6) Others: general weakness, cancerous fever is the late manifestation of the disease, seen in 1/4 of patients, and soon accompanied by disturbance of consciousness.

Symptoms mainly include increased intracranial pressure and general symptoms and local symptoms.

1. Increased intracranial pressure and general symptoms: due to rapid tumor growth and severe cerebral edema, the symptoms of increased intracranial pressure appear earlier and significantly, about 90% of patients have headaches, about 70% have nausea and vomiting, more than 70% have Papillary edema, 30% to 40% with fundus hemorrhage, causing vision loss of about 20%, about 15% have abductor nerve palsy, late 15% of patients have varying degrees of disturbance of consciousness, and may have cerebral palsy symptoms .

The general condition of the patient is poor, and some patients are obviously thin. About 20% of the patients have seizures, most of which are localized seizures. Because the tumors involve the frontotemporal lobe and the cerebral edema is extensive, they often have psychiatric symptoms. The common manifestation is The reaction is sluggish, the expression is indifferent, and the meningeal metastasis is mainly characterized by increased intracranial pressure and meningeal irritation, and local signs are rare.

2. Local symptoms: Because the tumor damages the brain more seriously, and often multiple, local symptoms are more significant, and the range of involvement is wider. According to the location of the tumor, corresponding signs are generated. More than 40% of patients have hemiplegia, about 15% have Hemiplegia, about 10% have aphasia, 5% are hemianopia, and in the cerebellum, there are nystagmus, ataxia, etc., and there may be symptoms of the posterior cranial nerve.

Examination of intracranial metastases

Blood test: Half of the patients' blood sedimentation speeds up, the peripheral blood leukocytes often increase, and red blood cells and hemoglobin decrease.

1. Skull X-ray film

It is often used in patients with cranial metastases. It is more helpful for the diagnosis of increased intracranial pressure, especially those with pineal displacement.

2. CT examination

CT is the first choice for the diagnosis of intracranial metastases. It can not only find brain metastases in most cases, but also show the shape, size, location, number of metastases, cerebral edema and secondary hydrocephalus and midline. The degree of structural shift, CT shows that the metastases are mostly located under the cortex or cortex, round or round, showing low density, equal density, high density or mixed density, or cystic mass, no nodules in the cyst. When accompanied by bleeding, it can show a high-density area or a liquid level. If the tumor grows fast, it can show necrosis and cystic changes in the central part of the tumor, surrounded by obvious low-density finger edema, adjacent to the lateral fissure pool or cerebral pool. When the pressure becomes smaller or disappears, the ipsilateral ventricle is compressed and deformed, displaced, and displaced. The pool around the brain stem may disappear partially or completely. At this time, the patient's condition is often very serious. Or agglomerate strengthening, the obvious enhancement often indicates that the tumor blood supply is rich, the bleeding can be concealed the original signs, easy to be confused with cerebral hemorrhage, ring-enhanced can be confused with brain abscess, located in the posterior cranial fossa often caused More obvious obstructive hydrocephalus, the displacement of the fourth ventricle is obvious, and the posterior cranial fossa, especially near the skull base, is often difficult to display due to the influence of artifacts. It can only be inferred from indirect signs, and the metastases of the thalamus and brainstem are often There is no obvious cerebral edema, and the degree of edema has no obvious relationship with the degree of tumor malignancy. The CT bone window position can clearly show the involvement of the skull. If the epidural metastasis is transferred, it can be seen that there is a fusiform or crescent-shaped high density along the skull plate. Density lesions, diffuse metastasis can be seen in the basal pool, bridge cerebral angle pool and other parts of high density shadow.

In addition, different pathological types of metastatic tumors have their own unique CT findings, such as lung adenocarcinoma and small cell undifferentiated cancer metastasis usually high-density nodules or ring-shaped lesions, uniform enhancement, edema, squamous cell carcinoma usually round A low-density mass with a thin ring-shaped reinforcement, half of which is single-shot.

3. MRI examination

MRI examination can not only provide the imaging features inherent in metastatic tumors, but also find multiple lesions that are easy to diagnose, because MRI can detect smaller tumors than CT, and multiple lesions are characteristic of metastases, for the posterior fossa and The lesions near the skull base are easily detected due to the removal of bone artifacts. Typical metastases are long T1, long T2 signals, and edema bands with longer signals around, due to edema on T2-weighted images. T2 signal, therefore, is more likely to detect lesions than T1-weighted images, especially for small lesions. Some characteristic metastatic tumors can show equal or slightly lower signals on T2-weighted images, and MRI can clearly show metastases. Adjacent cerebral gyrus and important structural involvement can help guide the surgical approach. Patients with hemorrhage in the tumor can show specific MRI manifestations of bleeding at different times. Due to the destruction of the blood-cerebrospinal fluid barrier, metastases can be significantly enhanced. It is clear that the meningeal thickening is easy to detect for diffuse type of meningeal metastasis.

4. Lumbar puncture The vast majority of intracranial metastases should not be used for this type of examination, often used to determine whether acute leukemia, non-Hodgkin's lymphoma, etc. have occurred intracranial metastases, cerebrospinal fluid can be used to guide clinical analysis after seeing tumor cells treatment.

Diagnosis and identification of intracranial metastases

diagnosis

In the case of primary tumors that have been identified and subsequent signs of intracranial space-occupying lesions, the diagnosis is not difficult. Early diagnosis of intracranial metastases before the onset of symptoms or the discovery of primary cancer often has certain difficulties. Therefore, for patients with intracranial tumor signs, the age is above middle age, there is a chronic history of other organs of the body, the general situation is poor, the disease develops rapidly, and the erythrocyte sedimentation rate increases, all of which should consider the possibility of intracranial metastases. Further observation and inspection are required. Should first take a chest radiograph to understand whether there is lung and bronchial cancer, pay attention to whether the lymph nodes are swollen, whether the liver is swollen, whether the thyroid gland, breast or prostate is swollen, whether there is abnormality in the gastrointestinal tract, urinary system or nasopharynx. . Further relevant auxiliary inspections should be carried out when necessary. CT scan and MRI have a positive value for the diagnosis of intracranial metastases. If you can find the primary cancer, or find cancer cells in the cerebrospinal fluid, or lymph node biopsy can find cancer cells are helpful for the diagnosis of intracranial metastases.

For patients without this disease, age over 40 years old, symptoms of increased intracranial pressure and signs of nervous system, and obvious symptoms, should be highly suspected intracranial metastases, after the head CT scan should pay attention to find the primary lesion, To further clarify the diagnosis. For patients with mild symptoms who have a CT scan of the head and suspected metastases by CT, the chest X-ray examination should be performed according to the primary tumor site. If necessary, bronchoscopy and chest CT scan can be performed. The situation is targeted for abdominal B-ultrasound, abdominal CT, digestive tract barium meal, rectal examination, gynecological B-ultrasound, etc., in order to be as clear as possible to facilitate treatment. Head MRI is performed as necessary to make a qualitative diagnosis as far as possible from imaging. Even so, a considerable number of patients still can't determine whether the tumor is metastasis after the intracranial surgery. They have to infer the source of the tumor according to the intraoperative and pathological findings, and then make corresponding examinations to determine the primary tumor site. . If the source of the tumor cannot be determined after a single tumor, the symptoms that may occur at any time should be closely observed to guide the diagnosis. In today's increasingly advanced neuroimaging methods, in addition to a comprehensive history and careful investigation, efforts should be made to improve the level of metastatic tumors from CT and/or MRI images. For patients with metastatic tumors located under the cortex, multiple, with obvious cerebral edema, the diagnosis is not difficult; the diagnosis level of single or cerebral edema with no obvious metastatic tumor should be improved.

Differential diagnosis

Primary brain tumor

According to the medical history, especially in patients with advanced systemic cancer, when the intracranial space is occupied, it is generally not difficult to identify. If necessary, it can be used for CT examination. The benign brain primary tumor has its own characteristics, easy to identify, malignant glioma. Sometimes difficult to identify with this disease, need to rely on biopsy, superficial meningeal metastases must be differentiated from small meningioma, the latter often have no obvious symptoms and peritumoral edema, there are skull destruction, still need to be with meningioma or skull Skull changes caused by external lesions are differentiated, but some brain primary tumors may be associated with brain metastases. In this case, it is impossible to identify them clearly. The primary brain tumors reported in the literature are mostly benign, such as meninges. Tumor, acoustic neuroma, pituitary tumor, etc., occasionally astrocytoma, brain metastases are more common in breast cancer and lung cancer, which is consistent with the general rule of brain metastases, breast cancer and lung cancer are common tumors in women and men, both tend to Central nervous system metastasis, the metastasis mechanism of this tumor is not clearly explained, probably because the age of benign brain tumors is similar to that of brain metastases, benign brain tumors have a longer survival period and have more blood supply and Tender tumor stroma, which provides favorable conditions for metastases.

2. Brain abscess

According to the medical history and necessary auxiliary examination, it is not difficult to identify with brain metastases. However, in rare cases, cancer patients may develop brain abscess due to the following factors. Pay attention to the diagnosis:

(1) The systemic resistance of cancer patients and the decline in immune function due to long-term use of hormones are prone to bacterial or fungal infections.

(2) Intracranial or skull base metastases cause intracranial and extracranial traffic due to radiotherapy or surgical treatment, facilitating bacterial invasion.

(3) Patients with primary or secondary lung cancer often have bronchial obstruction, causing lung abscess, which leads to brain abscess.

3. Infarction or cerebral hemo

At autopsy, 15% of patients with systemic cancer were associated with cerebrovascular disease, hemorrhagic and ischemic, half of them had symptoms before birth, 4% to 5% were intracerebral hematomas, and 1% to 2% were subdural hematomas. The cause of bleeding is mostly coagulation mechanism or thrombocytopenia. It is sometimes difficult to distinguish metastasis and stroke from clinical and CT findings, especially metastatic intratumoral hemorrhage, such as melanoma, chorionic epithelial cancer, bronchial lung cancer and adrenal tumor. Bleeding, because hemorrhage often comes from small blood vessels, the hematoma spreads along the nerve fibers, causing the latter to shift rather than destroy. If the hematoma is removed in time, the nerve function is expected to recover, so the surgery can not only save the patient's life, but also confirm the diagnosis. And to obtain a good quality of life, therefore, for those who are unclear in clinical diagnosis, craniotomy should be performed in time.

4. Cerebral cysticercosis

Must be differentiated from multiple brain metastases, patients with cerebral cysticercosis have a history of exposure to water, typical CT and MRI manifestations of multiple scattered brain or parenchyma in the brain parenchyma, focal cysts, varying sizes, small in the capsule Section, the density or signal of small nodules can be enhanced, if it is not enhanced, it is calcification, there is mild or no brain edema around the lesion, because the serological examination is not reliable, the suspected patients can be treated with experimental cysticercosis drugs, and Follow-up with CT and MRI can increase the detection rate.

For patients with slower onset, it should be differentiated from primary brain tumors. By means of the characteristics of the intracranial metastases mentioned above, the findings of primary cancer, CT or MRI found multiple lesions, intracranial The diagnosis of metastases can be determined. For patients with faster onset, it should be differentiated from brain abscess. Usually, patients with brain abscess have a significant history of infection. CT and MRI have different manifestations, which can be distinguished by extensive metastasis on the meninges. It should be differentiated from meningitis. The former has no signs of infection, but often has obvious mental symptoms. The protein content of cerebrospinal fluid is increased, but usually the cells are not significantly increased, and neutrophils are rarely seen.

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