Protruding and non-protruding adenomas of the stomach

Sixty-seven gastric adenomas found at gastrectomy in two ethnic groups (53 in Japanese and 14 in Icelandic patients) were investigated. Micrometric measurements were carried out on tissue sections. Adenomas being not higher than twice the measured height of the non-dysplastic adjacent gastric mucosa were regarded as non-protruding (n = 40) and those surpassing that limit as protruding (n=27). Measurements showed that 59.7% (n=40) of the 67 adenomas were non-protruding. The mean width in protruding adenomas (11.6 mm) surpassed the mean width of non- protruding adenomas (7.1 mm), suggesting that non-protruding adenomas may evolve into protruding forms. On the other hand, 13.6% (3 out of 22) of the protruding adenomas in Japanese patients were very small (< or = 5mm in width), implying that some small gastric adenomas grow from the outset in a protruding fashion. Conversely, 22.5% (n =9) of the 40 non-protruding adenomas measured 10 to 25 mm in width, suggesting that a proportion of the larger gastric adenomas may grow in a non-protruding, horizontal fashion without "becoming" protruding. Thus, similarly to colorectal adenomas, gastric adenomas may be classified into protruding and non-protruding. Micrometric measurements permit the correct assessment of the type of adenoma.