[Low-grade MALT-type non-Hodgkin lymphoma of the stomach with local recurrence 14 years following resection. Demonstration of clonal identity using polymerase-chain-reaction (PCR)].

So-called low grade B-cell lymphomas of MALT type occurring mainly in the gastrointestinal tract but also in the salivary glands, the thyroid and the lungs are indolent neoplasms with a prolonged clinical course and persistent localized disease at the site of origin. This behaviour sets them apart from their nodal counterparts, which are frequently generalized from onset. Their recognition within and their separation from accompanying reactive processes (e.g. chronic gastritis) is important but may be difficult on morphology alone. In the immediate past there have been reports on regression of gastric MALT type lymphomas after eradication of Helicobacter pylori. We observed a 68-year-old male patient who underwent partial gastric resection for persistent ulcer disease in 1979. A histological diagnosis of pseudolymphoma was established at that time. In 1993 he again had gastrointestinal bleeding. Endoscopy revealed ulcerations at the anastomosis. Biopsies showed a monoclonal infiltrate of centrocytoid B-cells with typical lymphoepithelial lesions, suggesting the diagnosis of low grade B-cell lymphoma of MALT type which was seen focally in multiple biopsies randomly taken from the gastric remnant. Review of the 1979 specimen revealed identical lesions. Polymerase chain reaction (PCR) on both specimens demonstrated identical products of rearranged Ig-heavy chain genes, thus confirming the monoclonality and establishing the clonal relationship of both lesions. Staging revealed no extragastric disease. Two courses of chemotherapy did not affect the mucosal infiltrates. Although the patient had been under antacid medication and the presence of Helicobacter pylori could not be demonstrated, antimicrobial treatment was given, after which follow-up biopsies were free of tumor and bacteria after 4 months.(ABSTRACT TRUNCATED AT 250 WORDS)