Atypical appearances of benign hyperplastic gastric polyps.

The vast majority of epithelial polyps of the stomach can be divided into two groups: (1) hyperplastic or regenerative polyps, and (2) adenomas. Of the two, hyperplastic polyps are much more common; they are nonneoplastic lesions which are typically asymptomatic, small, smooth-surfaced, and often multiple. Malignant transformation virtually never occurs in this group of polyps. Adenomas are true neoplasms; they are relatively large, have an irregular surface, and show a distinct tendency to undergo malignant transformation. In this paper the radiologic appearances of hyperplastic gastric polyps, with special reference to atypical findings, are discussed and illustrated. It is shown that simple hyperplastic polyps may present any or all of the radiologic criteria suggestive of gastric adenomas or even frank malignancy. Thus, while radiology plays a vital role in the initial detection and followup of gastric polyps, optimum clinical management of the patient is best based on knowledge of the histologic structure of the lesion obtained by endoscopy and biopsy.