Intracellular bacteria in Hodgkin's disease and sclerosing mediastinal B-cell lymphoma: sign of a bacterial etiology?

Background: The aetiology of Hodgkin's disease is still unknown more than 160 years after its original description. In recent years a viral aetiology was the preferred hypothesis. Epidemiological, clinical, laboratory, and histological findings, however, point rather to a bacterial aetiology. Methods: In the histological work-up of tissues from patients suffering from malignant lymphoma periodic acid-Schiff (PAS) stains are routinely done. In several bacterial infections intracellular PAS-positive material can be observed. We examined PAS-stained slides at magnifications of 1000× of six Hodgkin and twelve Non-Hodgkin patients. Results: We found PAS-positive diastase resistant intracellular rods and spheres in all Hodgkin patients and in all of the six patients suffering from sclerosing mediastinal B-cell lymphomas, but not in the other Non-Hodgkin lymphomas. Conclusions: The diastase resistant PAS-positive structures are compatible with intracellular bacteria. After gastric MALT-lymphoma and gastric non-cardia adenocarcinoma it appears that Hodgkin's disease and sclerosing mediastinal B-cell lymphomas may also be human tumors related to bacteria.