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Blog aimed at residents in surgery

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The primary gastric lymphoma: definition. Romeo Giuli MD, resident. School of General and Emergency Surgery. University of Siena.   Italy. October 2001.     Review Article. Primary gastric lymphoma is an uncommon malignancy that is increasing in incidence and represents approximately 2% to 7% of primary gastric malignancies. Primary gastric lymphoma is defined as an extranodal lymphoma arising in the stomach and is the most common site of extranodal lymphoma. PGC can spread to regional lymph nodes and become disseminated. Most primary gastric lymphomas are B cell in origin although occasional cases of T-cell and Hodgkin's lymphoma are seen. Secondary gastric lymphoma indicates involvement of the stomach as a part of a diffuse lymphoma arising elsewhere. Tertiary gastric lymphoma is recurrent lymphoma involving the stomach after treatment of a nodal lymphoma and is uncommon. Staging of gastric lymphoma based upon the Ann Arbor system includes stage I E, which is disease limited to the stomach without nodal spread. Stage II E 1 is tumor in the stomach with spread to adjacent contiguous lymph nodes. Stage II E 2 is tumor in the stomach with spread to lymph nodes that are non contiguous with the primary tumor. In 1994 Shimodaira and colleagues proposed a staging system for PGL based on the principles of the TNM system. A major deficit is the lack of a variable in the system to account for tumor grade that has been shown to be an indipendent predictor of survival ( 1 ). In the early 1980s the concept of lymphoma of mucosa associated lymphoid tissue (MALT) was introduced by Isaacson and Wright. In the gastric MALT-type lymphoma, both low grade and high grade histologies are encountered, and transformation in the course of the disease is a well recognized phenomenon. However the presence of primary, diffuse, large cell lymphoma without a low grade background is not unequivocally believed to be related pathogenetically to MALT-type lymphoma. Because the cytologic and clinical features of high grade lymphomas arising whithin a low grade background are similar to those of lesions without a low grade component, it appears reasonable to classify the latter as primary high grade MALT-type lymphomas ( 2 ). Mucosal surfaces along the gastrointestinal tract are usually devoid of lymphatic tissue, except for specific locations, such as Peyer's patches in the ileum. MALT is the lymphatic tissue found in the mucosa, usually acquired after inflammatory reactions or autoimmune processes, that triggers the influx of lymphocytes to the site. The presence of MALT can be regarded as an advanced chronic inflammatory process, wich is benign by its nature. But the presence of lymphatic tissue may give rise to lymphoproliferative processes, namely lymphoma of the non-Hodgkin type. It is believed that ongoing antigenic stimulation is the reason for the transformation from a benign inflammatory process to low-grade lymphoma, and subsequently, to high-grade lymphoma. Over the last two decades the increasing significance of H pylri in gastric pathology has been recognized. While it was originally found to be associated with peptic ulcer disease, it was subsequently found to play an important role in promoting other gastric pathologies: chronic gastritis, gastric MALT, MALT lymphoma and even gastric adenocarcinoma.It is not yet completely clear how H pylori triggers the gastric processes ( 3 ). References 1) J Stephens and J Smith. Treatment of primary gastric lymphoma and gastric mucosa-associated tissue lymphoma. J Am Coll Surg 1998; vol 187, n 3, 312-320. 2) M Raderer et al. Chemotherapy for the treatment of patients with primary high grade gastric B-Cell lymphoma of modified Ann Arbor Stages I E and II E. Cancer 2000; 88: 1979-85. 3) Danny Rosin et al. Gastric MALT lymphoma in a Helicobacter pylori-negative patient: a case report and review of the literature. J Am Coll Surg 2001; 192: 652-657. TO HOME PAGE next article Surgical Oncology net