Abstract
Purpose: :
To establish if H. pylori may play a role in the pathogenesis of conjunctival and orbital MALT lymphoma
Methods: :
Seven cases of MALT lymphoma (5 conjunctival, one orbit and one lacrimal gland) were selected for the study. Sections were cut at five micra and the slides were stained with hematoxylin and eosin, periodic acid Schiff (PAS), and four immunohistochemical stains (CD20, CD3, kappa and lambda) using the avidin–biotin–complex immunoperoxidase technique. Five micra unstained sections were used for molecular diagnosis using PCR amplification and Southern blot hybridisation techniques subjected for H. pylori urease B gene and/or nested PCR for the m2 region of H. pylori vacA gene.
Results: :
By light microscopy, the conjunctival epithelium was atrophic and showed the characteristic invasion by neoplastic lymphoid cells (lymphoepithelial lesion). The underlying stroma contained a population of small and medium–sized lymphocytes, most of which exhibited cleaved nuclei. In addition there were numerous plasma cells and plasmacytoid cells, some of which contained PAS–positive intranuclear inclusions (Dutcher bodies). Immunohistochemistry confirmed the B cell lineage in all seven lymphomas. Five of the seven specimens analysed by the nested PCR and Southern blot technique confirmed the urease B and vacA/M2 genes of the H. pylori DNA in the MALT lymphoma cells.
Conclusions: :
Based on these results, it appears that Helicobacter pylori may play a major role in the pathogenesis of conjunctival and orbital MALT lymphoma. We postulate that H.pylori therapy (tetracycline or triple therapy) may be used in the management of conjunctival and orbital MALT lymphoma. The different pathogenetic mechanisms of MALT lymphoma and H. pylori infection will be discussed.
Keywords: pathology: human • tumors • microbial pathogenesis: clinical studies