胃腸および消化器系

抽象的な

Melanosis “Coli” in Anal Heterotopic Gastric Mucosa: A Case Report and Review of the Literature

Walley DR, Greer R, Gonzalez MF, Subramony C

Background: Gastric heterotopia is the presence of gastric mucosa in a foreign anatomic location. It can occur anywhere in the gastrointestinal tract and has been well documented in the esophagus. Gastric heterotopia of the anorectum is a rare occurrence.

Case Report: We present a case of an asymptomatic adult male who underwent a colonoscopy during which an anal nodule was biopsied. Microscopic examination revealed oxyntic gastric mucosa with chronic active gastritis and melanosis coli. During a subsequent colonoscopy six years later, an abnormally pigmented area of anus was biopsied. Microscopic examination revealed antral gastric mucosa with chronic active gastritis.

A literature review showed that there have been 72 reported cases of gastric heterotopia of the anorectum. Only four of those case occurred in the anus.

Conclusion: To our knowledge, this is the first report of melanosis coli associated with gastric heterotopia of the anorectum as well as a shift in gastric mucosal type on repeat biopsy. We propose the term "outlet patch" for gastric heterotopia of the anorectum.