Summary and ConclusionDifferentiation of pseudoinflammatory colloid carcinoma from colitis cystica profunda is important. Despite the many clinical and histologic similarities, there are distinguishing features of which the surgeon should be aware. A favorable factor is the tendency of colloid carcinoma to grow slowly and metastasize late. Consequently, although it may be necessary to postpone radical treatment while establishing a diagnosis, the delay does not appear to affect prognosis adversely.