The normal squamocolumnar junction is circumferentially even and minimal irregularities are manifestations of gastroesophageal acid reflux.
BACKGROUND
The macroscopic appearance of the normal squamocolumnar junction (SCJ) is often described as serrated with short projections of columnar mucosa that extend into the esophagus. As studies of the normal SCJ are sparse, the aim of this study was to test the hypothesis that the normal SCJ is even and that irregularities are manifestations of acid reflux.


METHODS
Fifty asymptomatic subjects and 149 patients with symptoms suggestive of gastroesophageal reflux disease underwent endoscopy and 48-h pH monitoring with a pH electrode positioned immediately above the SCJ. The shape of the SCJ was assessed according to the Z-line appearance classification and correlated with clinical characteristics and the degree of esophageal acid exposure in the most distal esophagus.


RESULTS
Even SCJs without irregularities were significantly more common in asymptomatic subjects compared with patients (50% versus 10%, p < .001) and were never found in patients with erosive esophagitis. The median degree of distal esophageal acid exposure in individuals with an even SCJ was within normal limits. With increasing degree of irregularity of the SCJ, the frequency and duration of reflux episodes, the degree of distal esophageal acid exposure, and the prevalence of abnormal acid exposure increased progressively and significantly.


CONCLUSIONS
The shape of the normal SCJ is even and also minimal irregularities are a consequence of acid reflux, likely due to the formation of small areas of metaplastic columnar mucosa.
a Department of Gastroenterology , Clinical Sciences, Skåne University Hospital, Lund University , Lund, Sweden.
Mats
M
Guerrero Garcia Hall
b Department of Surgery & Urology, Division of Surgery , Clinical Sciences, Helsingborg Hospital, Lund University , Lund, Sweden.
Jörgen
J
Wenner
b Department of Surgery & Urology, Division of Surgery , Clinical Sciences, Helsingborg Hospital, Lund University , Lund, Sweden.
Stefan
S
Öberg
D000328:Adult; D016022:Case-Control Studies; D049631:Esophageal Sphincter, Upper / Q000033:anatomy & histology*; D050782:Esophageal pH Monitoring; D004943:Esophagogastric Junction / Q000033:anatomy & histology*; D004945:Esophagoscopy; D005260:Female; D005764:Gastroesophageal Reflux / Q000175:diagnosis* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008679:Metaplasia / Q000473:pathology; D008875:Middle Aged; D011446:Prospective Studies; D013548:Sweden
Barrett’s esophagus; GERD; adenocarcinoma; endoscopy-general; esophageal-disorders; pH monitoring