**2.1.3 Others**

128 Gastrointestinal Endoscopy

This proposed theory suggested that HGMP/CIP formed from ruptured proximal esophageal glandular retention cysts (Meining & Baubouj, 2010). The initial process starts with occlusion of esophageal glands in the proximal esophagus resulting in formation of retention cysts which is internally covered by columnar epithelium. With further enlargement of the cysts,

Retention cysts coalesce and enlarge Formation of HGMP/CIP

Fig. 3. Proposed acquired pathway through rupture of esophageal glandular retention cysts

in the proximal esophagus

Formation of retention cysts

*Formation from ruptured retention cyst of the proximal esophagus* 

they eventually rupture resulting in the formation of HGMP (Figure 3).

Others have proposed that development of HGMP/CIP in adult and children may be different based on differences in the mucin protein (MUC) staining. It has been suggested that two pathogenetic pathways maybe involved: focal upper esophageal mucosal misdevelopment in pediatric population and patchy metaplastic replacement of squamous mucosa in adults with gastroesophageal reflux disease. (Lauwers et al., 2005)
