Mucin histochemistry of the upper gastrointestinal tract.

Histochemically differentiated mucins have been studied in the mucosal lining of the esophagus and the stomach. Acid mucin was differentiated from neutral mucin by the alcian blue/PAS technique and sulphomucin by the high iron diamine/alcian blue technique. Neutral mucin secreted normally by the stomach mucosa was replaced by acid mucin in 17 of the 19 mucin secreting adenocarcinomas involving the lower third of the esophagus, and in 24 of the 28 mucin secreting gastric adenocarcinomas studied. The intestinal metaplasia (IM) seen in the gastric mucosa associated with adenocarcinoma, chronic gastric ulcer and chronic gastritis was classified according to the type of mucin secreted by the goblet cells. IM secreting sulphomucins was seen to be associated with gastric adenocarcinoma.