Gastric lymphosarcoma and pseudolymphoma: reappraisal of 12 cases of gastric lymphosarcoma.

Lymphoma localized to one organ is known to have a good prognosis. After a study of 131 cases of lymphosarcoma of the stomach Smith and Helwig(3) reported that 42 were in reality a benign lymphoproliferative disorder which has been termed pseudolymphoma of the stomach. Of our series of 12 cases, six are now thought to be pseudolymphoma. Jacobs(7) has enumerated the differentiating criteria. We have found a polymorphic cellular infiltrate, in nodular or diffuse pattern, associated with a fibrotic reaction located in the submucosa, muscularis or serosa, to be the most helpful criterion. The "good prognosis" associated with gastric lymphoma may be due partly to the difficulty in differentiating these two conditions and to the inclusion of cases of pseudolymphoma in any large series of these lymphomas.