What Is Primary Central Nervous System Lymphoma?

Central nervous system lymphomas include primary central nervous system lymphomas and systemic lymphomas. Secondary lymphomas that invade the central nervous system. The incidence of this disease is low, accounting for 1% to 3% of central nervous system tumors. With the application of immunosuppressants, the incidence of the disease has increased in recent years. Lymphoma primary to the central nervous system accounts for about 8%, and about 50% of cases of intracranial lymphoma are accompanied by systemic lymphoma. Central nervous system lymphoma can occur at any age, and most literature reports that it occurs at the age of 40 to 60 years; there is no significant difference between men and women, and most patients with AIDS lymphoma are men.

Basic Information

English name

central nervous system lymphoma

Visiting department

neurosurgery

Multiple groups

40 to 60 years old

Common causes

Reactive accumulation of non-neoplastic lymphocytes in the central nervous system

Common symptoms

Symptoms of high intracranial pressure such as headache and vomiting, and may be accompanied by mental changes

Causes of central nervous system lymphoma

There is no lymph circulation and lymph nodes in the central nervous system, and there are three theories of the etiology of lymphoma. It was thought that lymphoma originated from permembranous cells of the pia mater vessels, then invaded adjacent brain tissue, and expanded into the space around the perforating vessels, invading the deep hemisphere structures. The second theory is 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 monocytes is relatively low, and the brain's immune function is relatively weak. Under the stimulation of chronic antigens, the immune system responds in a polyclonal form. When the antigen is further stimulated and lymphocytes proliferate, Specific gene mutations may occur, form monoclonal proliferation, and develop into malignant lymphoma. The third theory is that lymph nodes or B-lymphocytes other than lymph nodes become tumors, and tumor cells migrate with the blood circulation. Because their cell surfaces carry central nervous system-specific adsorption markers, they only gather in the central nervous system, and the true primary The location is not clear, this theory can explain intracranial multiple lymphoma.

Clinical manifestations of central nervous system lymphoma

Central nervous system lymphoma has a short course, mostly within half a year. Its main symptoms and signs are caused by its pathological mass effect or diffuse cerebral edema. Early symptoms include high intracranial pressure symptoms such as headache and vomiting, which can be accompanied by Mental changes, such as personality changes and lethargy. Localized signs depend on the location and extent of the tumor. Limb numbness, paralysis, aphasia, and ataxia may occur. Epilepsy is rare. Clinical manifestations can be summarized into 4 groups:

Brain involvement symptoms

The main manifestations are headache, blurred vision, and personality changes. In addition, corresponding clinical manifestations will appear depending on the location of the lesion.

2. Symptoms of pia mater involvement

Such patients have significantly increased protein and lymphocyte counts during cerebrospinal fluid examination.

3. Eye involvement symptoms

Approximately 20% of patients with primary lymphoma are affected by the eye, and a slit lamp examination of the eye should be performed.

4. Symptoms of spinal cord involvement

Without special clinical manifestations, such as cytology and histology, preoperative diagnosis is very difficult.

Central Nervous System Lymphoma Examination

1. Lymphocytes may increase in peripheral blood leukocytes of patients

Lymphocytic elevation is not specific, and the cause is not very clear, but this feature can be used as an important reference for diagnosis of this disease.

2. Cerebrospinal fluid cytology

The protein content of patients' cerebrospinal fluid increased significantly, the cell count also increased, and the sugar content often decreased. Increased tumor cell and lymphocyte counts can be detected in the cerebrospinal fluid of half of the patients and was once considered the only way to confirm the diagnosis before surgery.

3. X-ray of head

In 50% of patients, plain radiographs of the skull are abnormal, signs of pineal gland displacement and increased intracranial pressure are common, and tumor calcification is rarely seen.

4. ECG

80% of patients with lymphoma have abnormal EEG and show localized or diffuse lesions.

5.CT inspection

CT scans show high-density or equal-density block shadows. Although there are imaging changes that are very similar to gliomas, the boundaries of malignant lymphomas are mostly clear. The tumors are significantly strengthened after the use of enhancers. There are obvious edema bands between tissues, and sometimes the lesions are multiple, which can also spread along the subventricular membrane.

6.MRI examination

Because it has the advantages of multi-directional scanning of the sagittal crown axis and higher resolution than CT, it has certain advantages in understanding the morphology of intracranial malignant lymphoma and its relationship with adjacent tissues. Lesions generally show equal or slightly lower signals on the T ₁ weighted image, and the signals are more uniform. After injection of GD-DTPA, the lesions were evenly strengthened, and some patients had a superior supraventricular ventricular ependymex, indicating that the tumor had infiltrated and expanded along the ependyma. There are reports that the high signal of intracranial malignant lymphoma tumor edema is not only indicative of increased brain interstitial water in the area, but also contains components of tumor cells spreading along the perivascular space.

7. Stereotactic biopsy

This is the simplest and most effective way to determine the nature of the lesion, and the damage is small, which plays a decisive role in the diagnosis and treatment of patients.

Central nervous system lymphoma diagnosis

An epidemiological survey found three categories of people to be vulnerable:

1. Organ transplant recipients.

2. AIDS patients .

3. People with congenital immunodeficiency (such as systemic lupus erythematosus, EB virus infection, rheumatoid, etc.).

The above 3 types of people should consider the possibility of central nervous system disease. If the patient has symptoms of increased intracranial pressure, combined with paresis or mental disorder, the proportion of lymphocytes in the leukocyte classification of peripheral blood is increased, and CT and MRI of the skull show a midline structure, multiple or diffusely growing lesions around the ventricle, the diagnosis is basically valid. However, to distinguish it from glioblastoma and meningioma, lumbar puncture can be used to collect cerebrospinal fluid for other auxiliary examinations such as cytology or stereotactic biopsy to confirm the diagnosis.

Central nervous system lymphoma treatment

General treatment

The use of medications such as hormones and dehydration can improve symptoms in the short term. About 40% of patients receiving corticosteroids (such as dexamethasone) can inhibit tumor growth and even make it fade, but the effect cannot be sustained.

2. Radiation therapy

The disease is very sensitive to radiotherapy and can quickly improve clinical symptoms. Radiotherapy should be preferred after a clear pathological diagnosis. About 90% of patients responded at the beginning of radiotherapy, but the overall effect was still poor. Because the disease often invades the ventricle, involving the pia mater and the eyes, and often recurring away from the original tumor site, it is necessary to perform whole brain radiotherapy after 40-50Gy, and then shrink the field to the local increase of the lesion and edema up to 60Gy; The infiltrated growers shrunk the field after 50 to 54 Gy of whole brain irradiation. If the cerebrospinal fluid has tumor cells or tumors invading the ventricle wall or spinal cord symptoms, the spinal axis should also be treated with radiation.

3. Surgical treatment

Due to the invasive and multifocal growth characteristics of the disease, the average survival time of a single surgery is only 3 to 5 months, but surgery can clearly diagnose and reduce intracranial pressure. Once the pathology is clear as lymphoma after surgery, radiotherapy should be performed immediately. If the disease has been considered, it is best to avoid surgical resection and use a stereotactic biopsy to determine the diagnosis.

4. Chemotherapy

It is used for recurrence after radiotherapy or combined with radiation therapy, and is an important part of comprehensive treatment of lymphoma. Chemotherapy drugs should be selected through the blood-brain barrier. Commonly used chemotherapy drugs are methotrexate (MTX), cyclophosphamide (CTX), vincristine (VCR), doxorubicin (doxorubicin), etc. .

5. Treatment after relapse

The prognosis of patients with lymphoma recurrence is rather poor. The most common lesions recur in situ, and there are other parts of the skull and even systemic recurrence. The course of the disease progresses very quickly, but if active treatment can also prolong survival, surgery can be performed according to the situation, followed by radiotherapy or chemotherapy.