Gastric lymphoma
Encyclopedia
Lymphoma
Lymphoma is a cancer in the lymphatic cells of the immune system. Typically, lymphomas present as a solid tumor of lymphoid cells. Treatment might involve chemotherapy and in some cases radiotherapy and/or bone marrow transplantation, and can be curable depending on the histology, type, and stage...
that originates in the stomach itself) is an uncommon condition, accounting for less than 15% of gastric malignancies and about 2% of all lymphomas. However, the stomach is a very common extranodal site for lymphomas (lymphomas originating somewhere else with metastasis
Metastasis
Metastasis, or metastatic disease , is the spread of a disease from one organ or part to another non-adjacent organ or part. It was previously thought that only malignant tumor cells and infections have the capacity to metastasize; however, this is being reconsidered due to new research...
to stomach). It is also the most common source of lymphomas in the gastrointestinal tract
Gastrointestinal tract
The human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....
.
Signs and symptoms
Most of the people primary gastric lymphoma affects are over 60 years old. Symptoms include epigastric pain, early satiety, fatigue and weight loss.Risk factors
Risk factors for gastric lymphoma include the following:- Helicobacter pyloriHelicobacter pyloriHelicobacter pylori , previously named Campylobacter pyloridis, is a Gram-negative, microaerophilic bacterium found in the stomach. It was identified in 1982 by Barry Marshall and Robin Warren, who found that it was present in patients with chronic gastritis and gastric ulcers, conditions that were...
- Long-term immunosuppressant drug therapy
- HIVHIVHuman immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
infection
Diagnosis
These lymphomas are difficult to differentiate from gastric adenocarcinoma. The lesions are usually ulcers with a ragged, thickened mucosal pattern on contrast radiographs.The diagnosis is typically made by biopsy
Biopsy
A biopsy is a medical test involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically...
at the time of endoscopy. Several endoscopic findings have been reported, including solitary ulcers, thickened gastric folds, mass lesions and nodules. As there may be infiltration of the submucosa, larger biopsy
Biopsy
A biopsy is a medical test involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically...
forceps
Forceps
Forceps or forcipes are a handheld, hinged instrument used for grasping and holding objects. Forceps are used when fingers are too large to grasp small objects or when many objects need to be held at one time while the hands are used to perform a task. The term 'forceps' is used almost exclusively...
, endoscopic ultrasound
Endoscopic ultrasound
Endoscopic ultrasound or echo-endoscopy is a medical procedure in endoscopy is combined with ultrasound to obtain images of the internal organs in the chest and abdomen. It can be used to visualize the wall of these organs, or to look at adjacent structures...
guided biopsy, endoscopic submucosal resection, or laparotomy
Laparotomy
A laparotomy is a surgical procedure involving a large incision through the abdominal wall to gain access into the abdominal cavity. It is also known as coeliotomy.- Terminology :...
may be required to obtain tissue.
Imaging investigations including CT
Computed tomography
X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...
scans or endoscopic ultrasound
Endoscopic ultrasound
Endoscopic ultrasound or echo-endoscopy is a medical procedure in endoscopy is combined with ultrasound to obtain images of the internal organs in the chest and abdomen. It can be used to visualize the wall of these organs, or to look at adjacent structures...
are useful to stage disease. Hematological parameters are usually checked to assist with staging and to exclude concomitant leukemia
Leukemia
Leukemia or leukaemia is a type of cancer of the blood or bone marrow characterized by an abnormal increase of immature white blood cells called "blasts". Leukemia is a broad term covering a spectrum of diseases...
. An elevated LDH
Lactate dehydrogenase
Lactate dehydrogenase is an enzyme present in a wide variety of organisms, including plants and animals.Lactate dehydrogenases exist in four distinct enzyme classes. Two of them are cytochrome c-dependent enzymes, each acting on either D-lactate or L-lactate...
level may be suggestive of lymphoma.
Pathophysiology
The majority of gastric lymphomas are non-Hodgkin's lymphoma of B-cell origin. These tumors may range from well-differentiated, superficial involvements (MALTMucosa-associated lymphoid tissue
The mucosa-associated lymphoid tissue is the diffusion system of small concentrations of lymphoid tissue found in various sites of the body, such as the gastrointestinal tract, thyroid, breast, lung, salivary glands, eye, and skin.MALT is populated by lymphocytes such as T cells and B cells, as...
) to high-grade, large-cell lymphomas. Sometimes, it's hard to differentiate poorly differentiated high grade B-cell gastric lymphoma from gastric adenocarcinoma clinically or radiologically, yet histopathology with immunohistochemistry
Immunohistochemistry
Immunohistochemistry or IHC refers to the process of detecting antigens in cells of a tissue section by exploiting the principle of antibodies binding specifically to antigens in biological tissues. IHC takes its name from the roots "immuno," in reference to antibodies used in the procedure, and...
is recommended to stain specific markers on the malignant cell that favor the diagnosis of lymphoma. Immunohistochemistry stains specific clusters of differentiation that are present on B-cells like CD20
CD20
B-lymphocyte antigen CD20 or CD20 is an activated-glycosylated phosphoprotein expressed on the surface of all B-cells beginning at the pro-B phase and progressively increasing in concentration until maturity....
. Cytokeratin
Cytokeratin
Cytokeratins are proteins of keratin-containing intermediate filaments found in the intracytoplasmic cytoskeleton of epithelial tissue. The term "cytokeratin" began to be used in the late 1970s when the protein subunits of keratin intermediate filaments inside cells were first being identified and...
is also a surface marker that is presented on epithelial cells, is stained histochemically and favors the diagnosis of epithelial tumors like adenocarcinoma.
Differentiating poor gastric lymphoma from adenocarcinoma is a must because the prognosis and modalities of treatment differ significantly.
Other lymphomas involving the stomach include mantle cell lymphoma
Mantle cell lymphoma
Mantle cell lymphoma is one of the rarest of the non-Hodgkin's lymphomas , comprising about 6% of NHL cases. There are only about 15,000 patients presently in the U.S. While it is difficult to treat and seldom considered cured, investigations into better treatments are actively pursued worldwide...
and T-cell lymphomas which may be associated with enteropathy
Enteropathy
-Types:Specific types of enteropathy include:* Gluten-sensitive enteropathy * Hemorrhagic enteropathy* Protein-losing enteropathy* Porcine proliferative enteropathy * Radiation enteropathy...
; the latter usually occur in the small bowel but have been reported in the stomach.
Treatment
Diffuse large B-cell lymphomas of the stomach are primarily treated with chemotherapyChemotherapy
Chemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....
with CHOP
CHOP
CHOP is the acronym for a chemotherapy regimen used in the treatment of non-Hodgkin lymphoma. CHOP consists of:* Cyclophosphamide, an alkylating agent which damages DNA by binding to it and causing cross-links...
with or without rituximab
Rituximab
Rituximab, sold under the trade names Rituxan and MabThera, is a chimeric monoclonal antibody against the protein CD20, which is primarily found on the surface of B cells...
being a usual first choice.
Antibiotic treatment to eradicate H. pylori is indicated as first line therapy for MALT lymphoma
MALT lymphoma
MALT lymphoma is a form of lymphoma involving the mucosa-associated lymphoid tissue , frequently of the stomach, but virtually any mucosal site can be afflicted...
s. About 60% of MALT lymphomas completely regress with eradication therapy. Radiation treatment for H. pylori negative gastric malt lymphoma, has a high success rate, 90% or better after 5 years. Second line therapy for MALT lymphomas is usually chemotherapy with a single agent, and complete response rates of greater than 70% have gain been reported.
Subtotal gastrectomy
Gastrectomy
A gastrectomy is a partial or full surgical removal of the stomach.-Indications:Gastrectomies are performed to treat cancer and perforations of the stomach wall....
, with post-operative chemotherapy
Chemotherapy
Chemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....
is undertaken in refractory cases, or in the setting of complications, including gastric outlet obstruction
Gastric outlet obstruction
Gastric outlet obstruction is a medical condition where there is an obstruction at the level of the pylorus, which is the outlet of the stomach. Individuals with gastric outlet obstruction will often have recurrent vomiting of food that has accumulated in the stomach, but which cannot pass into...
.