Mucosa-associated-like tissue lymphoma

Introduction of mucosa-associated tissue lymphoma Mucosaassociated lymphoblastoma (MAL) is a mucosa-associated lymphoid tissue that is a unique subtype of non-Hodgkin's lymphoma. It has a long course of disease, slow progression, and low incidence. It occurs in middle-aged men. The most common site of the disease is the stomach. basic knowledge The proportion of the disease: the disease is rare, the incidence rate is about 0.0001% - 0.0004% Susceptible people: no special people Mode of infection: non-infectious Complications: indigestion

Mucosa-associated tissue lymphoma

(1) Causes of the disease

Helicobacter pylory (Hp) infection can lead to chronic gastritis, peptic ulcer and gastric cancer. Hp is related to the occurrence of gastric MALT, but the exact mechanism is not very clear. Most people think that the interaction of environment, microorganism and host genetic factors It promotes the occurrence of gastric lymphoma. After Hp infection, lymphoid tissue can accumulate in the gastric mucosa, B cell follicles appear, and lymphoid epithelial lesions often form.

Monoclonal cell populations may occur in Hp-associated chronic gastritis and persist in secondary MALT, suggesting that MALT develops from chronic gastritis, more than 90% of gastric MALT lymphomas have Hp infection, and lymphomas of Hp-infected population The incidence was significantly higher than that of the normal population. Several study groups confirmed that gastric lymphoma was relieved after clinical clearance of Hp, but only effective for early mucosal and submucosal MALT. These phenomena indicate that Hp infection and gastric MALT lymphoma Relationship.

(two) pathogenesis

Basic research has found that Hp does not directly stimulate tumor B cells, but stimulates tumor cell proliferation by stimulating T cells in the tumor area; Hp does not stimulate T cells in non-MALT regions, which may explain that gastric MALT remains focal. tendency.

There are also some gastric MALT lymphomas with Hp infection that are ineffective for Hp treatment. There are no Hp infections in lymphomas of MALT in other sites. These phenomena suggest that the true pathogenesis and mechanism of MALT lymphoma remains to be elucidated.

MALT lymphoma can occur in any part of the stomach, the most common part is the gastric antrum, often multifocal, can be found in the site away from the main tumor, which often leads to postoperative recurrence, gastric MALT lymph Tumors are usually confined to the origin of the tissue, but sometimes present with multiple mucosal infiltration, such as disseminated to the small intestine, thyroid, parotid gland, etc., shallow invasive lesions can be seen under endoscopy, sometimes one or more ulcers can be seen, low malignant stomach The histological features of MALT lymphoma are similar to those of Peyer's bag. In the marginal zone, lymphoma infiltrating reactive follicles can be seen and diffusely spread to the surrounding mucosa. The most important feature is lymphatic epithelial foci, due to tumor cells. Invasion, destruction of the stomach glands or crypts, has a diagnostic significance, tumor cell morphology variation is very large, can be similar to the central cells of the follicular center, small lymphocytes or mononuclear B cells, a certain degree of plasma cell differentiation Sometimes it is difficult to make a diagnosis by morphological features alone, combined with immunohistochemistry and PCR technology to help diagnose.

MALT lymphoma cells express immunoglobulins, usually of the IgM type, which are almost identical to the immunophenotype of normal marginal B cells, CD19 CD20 CD79a, and CD5-, C10-, CD23-, cyclinD1-.

Molecular genetic analysis: 60% of low-grade malignant gastric MALT lymphoma showed chromosome 3 on chromosome 3, other abnormalities including t(11;18) and t(1;14), and 15% of c-myc and p53 mutations .

35% of gastric MALT lymphomas have a highly malignant transformation at the time of diagnosis, showing an increase in the number of large cells, which are fused into a cluster or flaky structure. Nakamura et al studied 179 cases of MALT lymphoma, which were found to be 6% lower. Degree of malignancy, 12% mixed grade, 31% of high-grade MALT lymphoma had abnormal expression of p53, while 93% of low-grade malignant, 88% mixed grade, 44% of high-grade MALT lymphoma had bcl-2 expression, indicating p53 mutation and Bcl-2 rearrangement is associated with malignant transformation.

Mucosa-associated tissue lymphoma prevention

The clear cause of lymphoma has not yet been fully discovered, and it is generally accepted that certain infectious factors may be associated with the onset of certain types of lymphoma. For example, the most common malignancy in patients with human immunodeficiency virus (HIV) infection is lymphoma, which is 60 to 100 times more common than the general population; Hodgkin's lymphoma, Burkitt's lymphoma, and nasal NK cell lymphoma. The incidence may be related to EB virus infection; HTLV? 1 virus is closely related to adult T cell lymphoma/leukemia; Helicobacter pylori is a possible cause of gastric MALT lymphoma; hepatitis C virus is associated with spleen lymphoma; Related to the occurrence of ocular adnexal lymphoma, pay attention to active prevention.

Mucosa-associated tissue lymphoma complications Complications, indigestion

Lymphocytes have undergone malignant transformation, which is called lymphoma. According to the "World Health Organization Lymphatic System Tumor Pathology Classification Standard", there are nearly 70 pathological types of lymphoma, which can be roughly divided into Hodgkin's lymphoma and non-Hodgkin. There are two major types of lymphoma. In China, Hodgkin's lymphoma accounts for 9% to 10% of lymphomas, and is a group of malignant tumors with relatively good curative effect; non-Hodgkin's lymphoma accounts for about 90% of all lymphoma cases, and for more than a decade The incidence rate is increasing year by year.

Mucosa-associated tissue lymphoma symptoms Common symptoms Abdominal pain Indigestion bloating

The onset is concealed and the development is slow. The common symptoms are upper abdominal pain, indigestion, acid reflux, etc. B symptoms are not common.

Staging, the best staging system has not been determined, the staging system in use has Musshoff improved Ann Arbor staging system, Blackledge staging system, AJCC system, etc., but can not reflect the depth of tumor invasion. In 1994, Japanese scholars reviewed 98 cases of gastric lymph. A new TNM staging system was proposed after the tumor, which is considered to have a better prognosis.

Examination of mucosa-associated tissue lymphoma

Endoscopic biopsy

For invasive patients, multiple biopsy should be performed, 4-8 points, once a month until clear diagnosis. Gastric biopsy immunohistochemical detection of Hp infection is sensitive and convenient. PCR technology and other molecular biology techniques identify monoclonal cell populations. Immunophenotypes, genetic alterations, etc. can help diagnose, judge prognosis and follow-up.

2.CT can find abnormalities in the stomach wall

Periplasmal lymph nodes, omental lymph nodes and adjacent organs can be found to assist in staging. Endoscopic ultrasonography (EUS) can accurately observe the extent of gastric wall invasion and lymph node involvement, with specificity of 90% to 100% and sensitivity of 39%. ~44%, combined with CT and EUS, makes the staging of laparotomy unnecessary.

According to clinical manifestations, symptoms, signs, choose to do peripheral blood, bone marrow, biochemistry, liver and kidney function, tumor markers, lactate dehydrogenase (LDH), serum blood protein (ALB), B-ultrasound and other tests.

Diagnosis and differentiation of mucosa-associated lymphoma

Diagnosis is mainly based on pathology, using morphological and clinical, immunological, genetic and molecular biological methods to comprehensively confirm the diagnosis, and should also test the evidence of HP infection.

It should be differentiated from pseudolymphoma, reactive lymphoid hyperplasia, mainly relying on histopathology.

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