Additional neoplasms and HCV infection in low-grade lymphoma of MALT type.

Several chronic inflammatory conditions and genetic alterations are likely to be involved in the pathogenesis of low-grade lymphoma of MALT type. In a well-characterized series of 27 patients with low-grade lymphoma of MALT type, we studied: (1) the incidence of other neoplasms, which might be indicative of genetic instability, apparently a characteristic of this disease; (2) the prevalence of serologic and molecular markers of HCV infection, which has been found in association with other lymphoproliferative disorders. Three patients had one or more additional cancers; a total of eight tumours, five of which occurred in the same patient, suggests the presence of some genetic instability in at least some cases of the disease. Rather unexpectedly, anti-HCV antibodies and HCV RNA sequences were documented in 50% of the patients examined, without elevation of serum transaminases. Of interest, the two patients with parotid and conjunctival MALT lymphomas, respectively, with a previous history of Sjögren's syndrome, were HCV positive. We suggest, for the first time, that HCV may be considered, in addition to Helicobacter pylori, as another potential infectious co-factor in the multistep pathogenesis of low-grade lymphomas of MALT type.