CHRONIC inflammatory lesions of the large and small intestine have been reported in the literature, from time to time,1 but not until Crohn, Ginzburg and Oppenheimer2 described the inflammatory condition which they called "regional ileitis" was it suggested that there was one group of such lesions which could be considered a clinical pathologic entity. Because no single gross or microscopic feature has been considered typical of the disease process, there has been much opposition to considering this a disease entity.3 Hadfield's4 excellent summary of the pathologic changes gives support to the contention that the lesion is a distinct one. Since publication of a study of 22 cases of this disease,5 careful examination of an additional 28 cases reveals the characteristic pattern of this disease, which will be discussed here.
It is well recognized that the disease is protean in its clinical manifestations. The pathologic observations