PRIMARY lymphoma of the gastrointestinal tract is diagnosed when tumor involvement of the intestine is the principal anatomic site of disease. The patient has abdominal symptoms that may be acute. Involvement of mesenteric nodes alone is not sufficient to place a patient in this classification. Nature of the Disease General.— A number of characteristics are summarized in Table 5.31-33 Staging.— A very simple staging was used for this discussion, ie, localized or extensive. Bowel perforations, or systemic symptoms, such as fever, weight loss or anemia, that are compatible with the local disease process do not change the staging in localized cases. The localized classification was used for those patients in whom the lymphoma involved the gastrointestinal tract alone or had spread to the regional mesenteric nodes only. There was no difference in the survival of those adult patients who did or did not have proven involvement of the regional