Gastric lymphoma is a rare, potentially malignant or malignant tumor originating from lymphoid tissue located in the stomach wall. Metastasis is rarely observed. Gastric lymphoma is manifested by premature saturation, pain in the epigastric region, nausea, vomiting, appetite disorders, weight loss and fever. It is diagnosed on the basis of medical history, clinical symptoms, examination data, radiography, CT, MRI, gastroscopy, biopsy, blood test for cancer markers and other studies. Treatment – anti-helicobacter therapy, gastric resection or gastrectomy, chemotherapy, diet therapy.
General information
Gastric lymphoma is a malignant non–leukemic neoplasm originating from lymphoid cells in the wall of the organ. It is usually characterized by a relatively favorable course, slow growth and rare metastasis, but the degree of malignancy of the tumor may vary. It is more often located in the distal part of the stomach. It is not associated with damage to peripheral lymph nodes and bone marrow. Gastric lymphomas account for 1 to 5% of the total number of neoplasms of this organ. They usually develop at the age of over 50 years. Men suffer more often than women. At the initial stages, the prognosis is favorable. The average five-year survival rate for gastric lymphomas of all stages ranges from 34 to 50%. The treatment is carried out by specialists in the field of oncology, gastroenterology and abdominal surgery.
Causes
The precursor of this neoplasm is lymphoid tissue located in the mucous membrane in the form of individual lymphocytes and clusters of cells. Under certain conditions (for example, with chronic gastritis that has arisen against the background of infection with Helicobacter pylori), such clusters form lymphoid follicles, in which areas of atypia may occur. Taking into account the fact that 95% of patients with gastric lymphoma have various strains of Helicobacter pylori detected during the examination, this infection is considered as one of the main causes of this pathology.
Along with Helicobacter pylori, the development of various types of gastric lymphomas can be provoked by other factors, including contact with carcinogenic substances, prolonged stay in areas with elevated radiation levels, previous radiation therapy, taking certain medications, excess ultraviolet radiation, nonspecific decrease in immunity, immune disorders in AIDS, autoimmune diseases and artificial suppression immunity after organ transplantation operations.
Classification
Taking into account the origin and features of the clinical course, the following types of gastric lymphomas are distinguished:
- MALT-lymphoma (abbreviation comes from the Latin mucosa-associated lymphoid tissue). It is part of the group of non-Hodgkin’s lymphomas. This gastric lymphoma develops from lymphoid tissue associated with the gastric mucosa. Usually occurs against the background of chronic gastritis. It is not accompanied by primary damage to peripheral lymph nodes and bone marrow. The degree of malignancy varies. It can metastasize to the lymph nodes.
- B-cell lymphoma. It is formed from low-differentiated B cells. Presumably it occurs as a result of the progression of MALT lymphomas, an indirect confirmation of this hypothesis is the frequent combination of the two listed types of gastric lymphomas. It has a high degree of malignancy.
- Pseudolymphoma. It is characterized by lymphoid infiltration of the mucous membrane and submucosal layer of the stomach. It proceeds benign, in some cases malignancy is observed.
Taking into account the peculiarities of growth , the following types of gastric lymphomas are distinguished:
- With exophytic growth. Neoplasms grow into the lumen of the stomach, are polyps, plaques or protruding nodes.
- With infiltrative growth. Neoplasia forms nodes in the thickness of the gastric mucosa. Depending on the features of the nodes in this group, there are tuberous-infiltrative, flat-infiltrative, gigantosclad and infiltrative-ulcerative forms of gastric lymphoma.
- Ulcerative. Gastric lymphomas are ulcers of various depths. They differ in the most aggressive course.
- Mixed. When examining a neoplasm, signs of several (more often – two) of the above types of tumor are found.
Taking into account the depth of the lesion determined during endoscopic ultrasound, the following stages of gastric lymphomas are distinguished:
- 1a – with damage to the surface layer of the mucous membrane.
- 1b – with damage to the deep layers of the mucous membrane.
- 2 – with a lesion of the submucosal layer.
- 3 – with damage to the muscle and serous layer.
Along with the above classification, a standard four-stage classification of oncological diseases is used to determine the prevalence of gastric lymphoma.
Symptoms
There are no specific signs, according to its clinical manifestations, gastric lymphoma may resemble stomach cancer, less often – gastric ulcer or chronic gastritis. The most common symptom is pain in the epigastric region, which often increases after eating. Many patients with gastric lymphoma note a feeling of premature saturation. Some patients develop an aversion to certain types of food. It is characterized by weight loss due to a feeling of fullness of the stomach and a decrease in appetite. There may be a critical decrease in body weight up to cachexia.
With gastric lymphoma, nausea and vomiting are often observed, especially against the background of eating excessive amounts of food, which further contributes to reducing portions, refusing food and subsequent weight loss. With the spread of the oncological process, stomach stenosis may develop. In some cases, patients with gastric lymphoma experience bleeding of varying severity (including small, with an admixture of blood in the vomit). There is a risk of developing severe complications – perforation of the stomach wall when it is germinated by a tumor and profuse bleeding when gastric lymphoma is located near a large vessel. Along with the listed symptoms, there is an increase in body temperature and profuse sweating, especially at night.
Diagnostics
The diagnosis is established taking into account complaints, medical history, external examination, palpation of the abdomen, laboratory and instrumental studies. Due to the nonspecific nature of the symptoms, it is possible to detect gastric lymphoma later, the literature describes cases when the time period between the appearance of epigastric pain and diagnosis was about 3 years. The main method of instrumental diagnosis is gastroscopy, which allows to determine the location and type of tumor growth. During endoscopic examination, gastric lymphoma may be difficult to differentiate with cancer, gastritis and non-malignated ulcer.
To clarify the diagnosis, the endoscopist takes material for subsequent histological and cytological examination. A distinctive feature of taking an endoscopic biopsy for gastric lymphomas is the need to take tissue from several sites (multiple or loop biopsy). To determine the prevalence of the oncological process, endoscopic ultrasound and CT of the abdominal cavity are performed. To detect metastases, an MRI of the chest and an MRI of the abdominal cavity are prescribed. Despite the diagnostic difficulties, due to the slow growth, most gastric lymphomas are detected at the first or second stage, which increases the likelihood of a successful outcome in this pathology.
Treatment
With localized, favorably flowing MALT lymphomas, eradication antihelicobacter therapy is carried out. It is permissible to use any treatment regimens with proven effectiveness. In the absence of a result, after applying one of the standard regimens, patients with gastric lymphoma are prescribed complicated three-component or four-component therapy, including the introduction of proton pump inhibitors and several antibacterial agents (metronidazole, tetracycline, amoxicillin, clarithromycin, etc.). If complicated schemes are ineffective, depending on the stage of gastric lymphoma, chemotherapy or systemic therapy is performed.
In other forms of gastric lymphoma and MALT lymphomas spreading beyond the submucosal layer, surgical intervention is indicated. Depending on the prevalence of the process, gastric resection or gastrectomy is performed. In the postoperative period, all patients with gastric lymphoma are prescribed chemotherapy drugs. In advanced cases, chemotherapy or radiation therapy is used. Chemotherapy can provoke ulceration and perforation of the stomach wall (including asymptomatic), therefore, when using this technique, CT scans are regularly performed to detect free fluid and gas in the abdominal cavity. In the late stages of gastric lymphoma, there is a threat of developing gastric stenosis, gastric perforation or gastric bleeding, so operations are recommended even for stage III and IV tumors.
Due to slow growth, late invasion into the deep layers of the stomach wall and rather rare metastasis, the prognosis for gastric lymphomas is relatively favorable. The use of eradication therapy in the early stages of MALT lymphoma provides complete remission in 81% of patients and partial remission in 9% of patients. Radical surgical interventions are possible in 75% of cases. The average five-year survival rate for stage I gastric lymphoma is 95%. At stage II, this indicator decreases to 78%, at stage IV – to 25%.