Clone-specific PCR reveals wide dissemination of gastric MALT lymphoma to the gastric mucosa

The development of low-grade gastric mucosa-associated lymphoid tissue (MAL T) lymphoma is closely associated with Helicobacter pylori infection, Despi te its indolent clinical course and prolonged localization to the site of o rigin, the lymphoma frequently presents with multifocal lesions, However, t he true extent of tumour involvement in the gastric mucosa is unclear, sinc e reactive appearing lymphocytic infiltrates are always present and could c ontain tumour cells that are not readily identifiable on cytological ground s. Gastrectomy specimens of four MALT lymphoma cases were studied by microd issection and clone-specific polymerase chain reaction (CS-PCR) and of a fu rther case with t(1;14)(p22;q32) by immunohistochemistry for BCL10 protein, which acted as a tumour marker for tumour cells carrying the translocation , CS-PCR revealed that tumour cells were commonly present in histologically non-lymphomatous lymphocytic infiltrates microdissected from areas well se parated from tumour lesions, Tumour cells were also frequently found in inf iltrates microdissected from the resection margins, These findings were rei nforced by direct identification of tumour cells, as recognized by strong B CL10 nuclear staining, in non-lymphomatous lymphocytic infiltrates in the c ase with t(1;14)(p22;q32), The results show that gastric MALT lymphoma diss eminates widely within the gastric mucosa without necessarily forming diagn ostic lesions, Copyright (C) 2000 John Wiley & Sons, Ltd.