回腸のBlind Loopに発生した胃上皮化生

Gastric Gland Metaplasia in the Ileal Blind Loop

　胃以外における消化管に胃腺上皮を見ることは極めて稀であるが，メッケル憩室，食道異所性胃上皮¹⁾，十二指腸²⁾³⁾，腸管二重症⁴⁾⁵⁾等に見られるという報告がある．しかしそれらの異所性胃上皮のほとんどは先天的に発生した上皮と考えられ，明らかに後天的に発生したと考えられる報告は今までのところ，われわれの知る限り1例のみである．

　われわれは小腸にBlind Loopを設置した20年後の患者の小腸切除標本の粘膜に散在性の幽門腺様腺管，そして壁細胞，主細胞，副細胞より成る胃底腺上皮を認めたのでその報告を行ない若干の文献的考察を行なった．

　Congenitally developed gastric heterotopia in the organs other than the stomach is frequently seen in patients with Meckel's diverticulum and less frequently in intestinal duplication. On the other hand, acquired type of gastric metaplasia is that of pseudopyloric gland found in the duodenum and small and large intestine. The true gastric metaplasia in the intestine below the ligament of Treitz, however, had not been reported until 1963 when Ming et al. described a case of regional ileitis in which he represented true gastric gland in the ileum. Another report by Trier et al. in 1973 was on ectopic gastric mucosa in the jejunum with celiac sprue.

　This is a case report of gastric metaplasia in the ileal blind loop. The patient, a 56-year-old man, had undergone side-to-side ileal bypass surgery because of acute intestinal obstruction twenty years previously. The specimen of the ileal blind loop resected recently due to recurrent intestinal obstruction disclosed patchy appearance of true gastric glands consisting of chief cells, parietal cells and mucous neck cells. The true gastric glands were considered to represent an acquired metaplasia because there was an extensive pseudopyloric gland metaplasia in the mucosa of the specimen, in which dilated cystic glands were scattered in the deep zone of the mucosa propria, occasionally showing transformation from dilated cystic glands into pseudopyloric glands or true gastric glands. Moreover, both dilated cystic glands and pseudopyloric glands seemed to be closely related to ulcer healing. Therefore, true gastric gland is considered to be derived from metaplastic pseudopyloric gland, probably under the influence of alterations of intestinal condition such as long-standing ulcerative process, stasis of the intestinal contents, and so on.