An Aggressive Form of MALT Lymphoma of the Stomach with Pancreas Infiltration.

Introduction: MALT lymphoma accounts for 7-8% of all B-cell lymphomas and at least 50% of primary gastric lymphoma, with the highest incidence at between 50 and 60 years of age. Aggressive forms are rare, as are indications for multi-visceral resection.

Case Study: A patient, 33 years old, was admitted to the tertiary hospital due to a biopsy at a small community hospital confirming adenocarcinoma of the stomach. She was Helicobacter pylori positive. CT showed thickening of the fundus and corpus wall, up to 2.7. cm., with numerous lymph nodes, along the small curvature and in the peripancreatic region, up to 1.5 cm in size. There was close contact between the changed and tumorous posterior wall of the stomach and the anterior surface of the pancreas. Neoplasm of the stomach was found that had infiltrated the body and tail of the pancreas and spleen hilum. Infiltration of the left crura of the diaphragm was also found, ex tempore biopsy showed inflammatory infiltration without elements of neoplasm. Total gastrectomy with omentectomy, and subtotal pancreatectomy and splenectomy were performed. Definitive patho-histological diagnosis confirmed MALT lymphoma of the stomach with pancreas infiltration, but no tumor cells were found on the spleen. Additional staining and immunohistological examination of the specimen from the community hospital showed that this was a misdiagnosis of carcinoma, and the specimen also contained MALT lymphoma.

Discussion: MALT lymphoma frequently occurs in the stomach. For patients with MALT, systematic staging is indicated. If MALT is considered in the differential diagnosis, multiple random systematic biopsies within the stomach wall are needed to optimize diagnostic accuracy. Samples should be subject to immune phenotype analysis6. The main tumor cells of MALT are: CD 20+, CD 5-, CD 10-, CD 23-, CD 43+-. It is obvious that this kind of analysis cannot be accomplished in a small community hospital in a poor country such as Bosnia and Herzegovina, and suspicion of MALT indicates referral to a tertiary center. Although the long term risk of transformation of MALT lymphoma into the aggressive form is low9, this case of the aggressive form of MALT indicates the importance of systematic staging.