Hyperplasia of the submucosal glands of the columnar-lined oesophagus

To evaluate the presence of multi-layered epithelium (ME) and to compare the distribution, size and morphology of the oesophageal submucosal glands (SMG) beneath reflux exposed metaplastic columnar mucosa with those of normal squamous epithelium in patients with columnar-lined oesophagus (CLO).

In eight oesophageal resection specimens, the SMG of the metaplastic segments were significantly larger than those in the squamous segments of patients with CLO (0.81 versus 0.56 mm(2) , P = <0.001). There was an accumulation of SMG close to the neosquamocolumnar junction (NSCJ), as indicated by a higher median frequency of SMG (0.080 SMG/mm) compared with that of the squamous (0.013 SMG/mm) and metaplastic segments (0.031 SMG/mm) (P = 0.022). The frequency of ME was significantly higher in the metaplastic compared with the normal squamous segments (1/158 mm and 1/341 mm, respectively, P = 0.028) and ME was found almost exclusively (96%) in direct connection with the excretory ducts of SMG.

Hyperplasia of SMG in the metaplastic segment, accumulation of SMG near the NSCJ, the presence of ME in connection with the excretory ducts of SMG and metaplasia are all reflux-induced morphological changes, possibly induced by stimulation of progenitors in the excretory ducts of the SMG.