Lymphoma is the cancer of the lymphatic system. The lymphatic system is a network of thin tubes and lymph nodes that run throughout the body. Primary gastric lymphoma (PGL) is the most common extranodal site of non-Hodgkin lymphoma and represents 30–40% of all extranodal lymphomas. It also represents 4–20% of all non-Hodgkin lymphomas (NHL) and approximately 5% of primary gastric neoplasms. The frequent histological subtypes of PGL are marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT) and diffuse large B-cell lymphoma (DLBCL).
MALT stands for mucosa-associated lymphoid tissue. The mucosa is the moist tissue that lines some organs and body cavities, including the nose, mouth, lungs, and digestive tract; thus, MALT lymphoma starts in the body organs, and not in the lymph nodes.
There are two main types of lymphocytes: B-cells and T-cells. MALT lymphoma that starts in the B cells is known as B cell lymphoma. These low grade (indolent) lymphomas are most often diagnosed in the stomach (called gastric MALT), but they can also develop in the lung, thyroid, salivary glands, eye, skin or soft tissues (called non- gastric MALT). Besides, MALT lymphoma usually grows slowly. And most people have early-stage (localized) MALT lymphoma when diagnosed.
MALT Lymphoma, also known as marginal zone lymphoma, is typically low-grade neoplasia, characterized by a dense lymphoid infiltrate mainly composed of small-size lymphocytes that invade and destroy gastric glands, configuring the so-called ‘lymphoepithelial lesion’ which is pathognomonic of lymphoma. Although a specific antigenic profile of MALT lymphomas does not exist, the B-cells sharing the immunophenotype with marginal zone B-cells present in the spleen, Peyer’s patches and lymph nodes, gastric lymphoma is CD20+, CD5+; CD10−, CD23−, and cyclin D1−. Also, low-grade MALT lymphoma of the stomach is strongly associated with H. pylori infection.
The main symptoms are nonspecific and include fatigue, fever, nausea, constipation, weight loss, and anemia. Other symptoms depend on the affected organs: abdominal pain in cases with gastric involvement, recurrent respiratory infections in cases with pulmonary involvement, and visual impairment in cases with lacrimal gland involvement. In general, patients do not have lymphadenopathy. Diagnosis is based on histology of the lesion, as in all lymphomas, a complete blood count and biochemical analysis. Endoscopic examination is required for gastrointestinal or pulmonary lymphoma. MRI and CT scanning are required to determine the stage of the disease. Bone marrow biopsy is also performed.
The discovery of Helicobacter pylori (HP) role in the pathogenesis of gastric lymphomas has radically changed the prognosis of these patients, with an increased survival rate just by eradicating this pathogen. Current gastroenterology and oncology international guidelines have established that first-line therapy in the early stages is the eradication of HP. In contrast, in those with advanced stages, adjuvant anti-tumor therapy is needed.
Treatment is tailored to the type, stage, and grade. Most slow-growing, localized MALT lymphomas respond well to treatment. Local therapies such as radiation therapy or surgery are used with early-stage MALT lymphomas that occur in areas other than the stomach. More advanced MALT lymphomas (stage 3 or 4) are usually treated with chemotherapy regimens such as CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone) or CVP (cyclophosphamide, vincristine and prednisolone), or with single-agent chemotherapy such as chlorambucil. The monoclonal antibody, rituximab may also be used, either on its own or in combination with chemotherapy.
Source:- MALT lymphoma Market
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