Functioning heterotopic oxyntic mucosa in the rectum.

Heterotopic gastric mucosa in the rectum is an extremely rare condition. It is significant clinically because it may cause rectal bleeding or may present as a mass which must be distinguished from a neoplasm. Another case is described, and the 9 previously reported cases are reviewed. This is the first case to be reported in which the heterotopic mucosa was actually shown to secrete measurable acid in response to pentagastrin. The lesion could be accurately demarcated using a pH-probe after pentagastrin stimulation, a maneuver which was helpful in the complete surgical excision of the lesion.