Central Nervous System Lymphoma
Introduction
Introduction to central nervous system lymphoma Central nervous system lymphomas include primary central nervous system lymphomas and systemic lymphomas that invade the secondary lymphoma of the central nervous system. The incidence of the disease is low, accounting for 1% to 3% of central nervous system tumors. With the application of immunosuppressive agents, the incidence of this disease has increased in recent years. Lymphoma originating in the central nervous system accounts for about 8%, and about 50% of cases of intracranial lymphoma are associated with systemic lymphoma. Central nervous system lymphoma can occur at any age, most of the literature reported that the age of onset is 40 to 60 years old; there is no significant difference between male and female, AIDS lymphoma patients are mostly male. basic knowledge The proportion of the disease: the disease is rare, the incidence rate is about 0.0003%-0.0008% Susceptible people: no specific population Mode of infection: non-infectious Complications: nausea and vomiting
Cause
Causes of central nervous system lymphoma
(1) Causes of the disease
There are no lymphatic circulation and lymph nodes in the central nervous system. There are three theories about the cause of lymphoma. It is thought that lymphoma originates from the pericytes of the soft meningeal blood vessels, and then invades the adjacent brain tissue and extends to the perivascular space. The deep structure of the hemisphere, the second theory holds that lymphoma is caused by the reactive accumulation of non-neoplastic lymphocytes in the central nervous system. Because the brain tissue lacks the lymphatic system, the number of mononuclear inflammatory cells is relatively low, and the immune function of brain tissue is relatively high. Weak, under the stimulation of chronic antigen, the immune system reacts in a polyclonal form. When the antigen is further stimulated and lymphocytes proliferate, specific gene mutations may occur, forming a monoclonal proliferation and developing into a malignant lymphoma. The third theory It is believed that B lymphocytes other than lymph nodes or lymph nodes become tumors, and tumor cells migrate with the blood circulation. Because the cell surface carries a central nervous system-specific adsorption marker, it only accumulates in the central nervous system, but the true primary site is unclear. This theory can explain multiple lymphomas in the brain.
(two) pathogenesis
Lymphoma can occur in any part of the central nervous system, but most of it occurs on the screen. About 50% of lymphomas occur in the cerebral hemisphere, the posterior fossa is 10% to 30%, and the upper and lower sides are affected by 18%. The lesions occur in the basal ganglia, the corpus callosum, the periventricular white matter and cerebellar vermis, the pia mater, the choroid plexus and the transparent septum are often involved. The intracerebral lymphoma can be a focal mass lesion or a diffuse invasive growth, tumor There is no capsule, focal space can be multiple, often located in the ventricle, is a solid lesion, the boundary is unclear, the surrounding edema is obvious, the texture can be soft, hard, blood supply is rich, grayish white or purple, rarely bleeding Necrotic cystic changes, diffuse growth of the tumor can be normal, may have subarachnoid expansion, resulting in thickening gray-white, which belongs to B-cell lymphoma, more common in small cell type and large cell type.
Microscopically, the diffuse tumor cell infiltration is far beyond the general boundary. The cells are dense, the cytoplasm is less, mostly round or oval, the nucleus is obvious, long or distorted, chromatin is scattered and scattered, and nuclear fission is common. Sometimes, the tumor cells are distributed around the blood vessels in sleeves. Sometimes, tumor cells distributed in the brain tissue around the tumor are visible, and even scattered or clustered tumor cells can be seen in the brain tissue away from the tumor. It constitutes the basis of multi-center or recurrence of tumors. The tumors are rich in blood supply, mostly small blood vessels below medium level. The incidence of pia mater involvement in autopsy is about 12%.
Prevention
Central nervous system lymphoma prevention
1. The cause of the disease is likely to be related to some bacterial viruses, but the mechanism of tumorigenesis is very complicated. Infection is only one of the external factors. At present, there is no tendency to spread the lymphoma and the mass. Therefore, as a relative of lymphoma patients, the risk of lymphoma is not significantly higher than the general population.
2. If you have received high-dose, multi-course chemotherapy, especially some drugs that affect reproductive function, it is recommended that patients avoid birth during treatment; for the child's health and family happiness, it is also recommended to consider fertility after 3 years of treatment. .
3. Reducing environmental pollution, maintaining good living habits, timely treatment of certain chronic inflammatory diseases of the body, and improving the immune function of the body may not only reduce the incidence of lymphoma, but also reduce the incidence of other malignant tumors.
Complication
Central nervous system lymphoma complications Complications, nausea and vomiting
1. Early symptoms of high intracranial pressure, causing headache, vomiting, etc.
2. Associated with mental abnormalities, personality changes, lethargy and other manifestations, localized tumors, can lead to numbness, paralysis, aphasia, ataxia, epilepsy and other complications.
3. Central nervous system lymphoma is often caused by other lymphoma metastasis, and will also be associated with the complications of other systemic lymphoma.
Symptom
Symptoms of central nervous system lymphoma Common symptoms Mild sputum Immunodeficiency ataxia Mental disorder Limb or trunk numb sleepiness Increased intracranial pressure Nausea and vomiting
Lymphoma has a short course of disease, mostly within half a year. Its main symptoms and signs are caused by pathological space-occupying lesions or diffuse brain edema. Early manifestations include high intracranial pressure symptoms such as headache and vomiting, and may be accompanied by mental symptoms. Changes, such as personality changes and lethargy, limitations of physical signs depending on the location and extent of the tumor, limb numbness, paralysis, aphasia and ataxia, etc., epilepsy is rare.
Clinical performance is divided into 4 groups:
1. Symptoms of brain involvement (30% to 50%) Mainly manifested as headache, blurred vision, personality changes, and the corresponding clinical manifestations according to the location of the lesion.
2. Pyocardial involvement symptoms (10% to 25%) In such patients, protein and lymphocyte counts were significantly increased during cerebrospinal fluid examination.
3. Symptoms of eye involvement (10% to 20%) Because about 20% of patients with primary lymphoma are affected by the eye, patients with suspected central nervous system lymphoma should be examined for slit lamp.
4. The spinal cord involvement is less than 1%.
Examine
Central nervous system lymphoma examination
1. Lymphocytes in peripheral blood leukocytes can be increased in lymphocytes, and lymphocytes are not specific. The reason is not very clear, but this feature can be used as an important reference for the diagnosis of this disease.
2. Cerebrospinal fluid cytology examination The protein content of cerebrospinal fluid in almost all patients increased significantly, the cell count also increased, and the sugar content was often reduced. In half of the patients, the tumor cells and lymphocyte counts were detected in the cerebrospinal fluid. This degree was considered as preoperative. The only way to diagnose it.
3. Head X-ray film 50% of patients with abnormal head flat film, common pineal body displacement and increased intracranial pressure, rarely seen tumor calcification.
4. Electrocardiogram 80% of lymphoma patients with EEG abnormalities, showing localized or diffuse lesions.
5. CT examination CT scan shows high-density or equal-density block shadows. Although there are imaging changes very similar to gliomas, the borders of malignant lymphomas are mostly clear, and the tumors are obviously enhanced after application of the enhancer. There is a marked edema zone between the tumor and the normal brain tissue, and sometimes the lesion is multiple, and it can also spread under the ependym.
6. MRI examination MRI examination has the advantage of higher resolution than CT because of the multi-azimuth scan of the sagittal axis. It has certain advantages in understanding the morphology of intracranial malignant lymphoma and the relationship with adjacent tissues. The lesion is generally in the TI-weighted image. On the upper signal or slightly lower signal, the signal is more uniform. After injection of GD-DTPA, the lesion is evenly strengthened. Some patients have adjacent ventricle ventricular duct membrane enhancement, suggesting that the tumor has expanded along the ependymal membrane. It is reported that the skull The high signal of peritumoral edema of malignant lymphoma not only indicates an increase in brain interstitial water at this site, but also contains components of tumor cells that are scattered along the perivascular space.
7. Stereotactic biopsy is the simplest and most effective method to determine the nature of the lesion, and the damage is small, which plays a decisive role in the diagnosis and treatment of the patient.
Diagnosis
Diagnosis and diagnosis of central nervous system lymphoma
diagnosis
Lymphoma has no special clinical manifestations, such as no cytology and histological data, preoperative diagnosis is very difficult, epidemiological investigation found that three types of people have susceptibility:
1 organ transplant recipient.
2 AIDS patients.
3 congenital immunodeficiency (such as systemic lupus erythematosus, EB virus infection and rheumatoid), the above three categories of patients with central nervous system diseases should consider the possibility of the disease, such as patients with increased intracranial pressure symptoms, In combination with sputum or mental disorders, the proportion of lymphocytes in the peripheral blood leukocyte classification is increased, the CT and MRI show the midline structure, and the lesions surrounding the ventricle or diffuse growth are basically established, but with glioblastoma, Identification of meningioma, etc., can be used to confirm the diagnosis by collecting the cerebrospinal fluid through the cerebral cytology or stereotactic biopsy.
Differential diagnosis
1. The metastatic tumor is located at the junction of gray matter and white. The CT non-enhanced scan is mostly low density. The MRI imaging is a long T1 long T2 abnormal signal, while the lymphoma is mostly low or equal T1 and other T2 signals. After injection of contrast agent, the lesion It is obviously nodular, and the lesions are larger, often with central necrosis, while lymphoma is relatively rare. The edema around the metastasis is very obvious. Some patients can provide a history of tumors outside the central nervous system.
2. MRI of gliomas is characterized by long T1 and T2 abnormal signals, and its invasive growth characteristics are obvious, and the boundary is unclear. Some types of gliomas, such as oligodendroglioma, may have calcification, colloid. The herma cell tumor is more irregular and has a ring shape or a branch shape.
3. Meningioma is located on the surface of the brain adjacent to the meninges. The shape is round, the boundary is clear, and there are surrounding gray matter pushing signs. Non-enhanced CT is characterized by high density and MRI is T1 signal such as T1. After injection of contrast agent, tumor Uniform enhancement, there is a meningeal "tail sign", but it should be noted that the meningeal "tail sign" is not unique to meningioma, any lesion invading the meninges, there are "tail signs" may appear.
4. The age of onset of infectious lesions is relatively young, some have a history of fever, and the enhanced scan of bacterial infections is mostly ring-enhanced, and multiple sclerosis is mostly patch-like enhancement.
