Association of gastric and Waldeyer's ring lymphoma: a molecular study.

The coexistence of Waldeyer's ring and gastrointestinal non-Hodgkin's lymphomas at presentation is well known. Moreover, localized gastrointestinal relapses following successful treatment of lymphomas of Waldeyer's ring and thyroid lymphomas occurring after a prolonged disease-free interval have also been described. We report two cases of concomitant lymphoma in Waldeyer's ring and stomach. On the basis of the molecular analysis of the immunoglobulin heavy chain gene rearrangements, two different patterns of concomitant involvement by a lymphoma in Waldeyer's ring and in the gastrointestinal region seem to exist. One is represented by the preferential dissemination of the lymphoma from one site to the other, the second by the apparently independent growth of clonally unrelated lymphomas at each site.