Primary Gastric Lymphoma (PGL) accounts for fewer than 5% of gastric neoplasms. However, PGL comprises two thirds of all primary GI lymphomas because the stomach is the most commonly involved organ in extranodal lymphoma. PGLs are usually B-cell, non-Hodgkin lymphomas. Most PGLs occur in the distal stomach.
Patients typically present in their sixth decade with symptoms similar to those of gastric adenocarcinoma (epigastric pain, weight loss, anorexia, nausea, vomiting, and occult GI bleeding). Diagnosis is typically made using endoscopy, and staging to detect systemic disease is performed using CT of chest/abdomen/pelvis, bone marrow biopsy, and biopsy of enlarged peripheral lymph nodes.
Therapy of PGL has been advanced by the recognition that low-grade PGLs have features resembling mucosa-associated lymphoid tissue (MALT) and that the majority of low-grade MALT lymphomas are associated with H. pylori infection.
Thus, first-line therapy for low-grade MALT lymphomas is use of antibiotics directed at H. pylori eradication, which leads to complete remission rates of 70% to 100%. Chemoradiation therapy is used as salvage therapy for failure of antibiotics. High-grade or non-MALT lymphomas are generally treated with chemoradiation therapy alone, with surgical resection reserved for those who fail chemoradiation or in emergency cases of hemorrhage or perforation.