Inlet patch: an inconspicuous lesion needs more spotlight.

Esophageal inlet patch is considered a congenital anomaly, a remnant of gastric mucosa which is left behind during the descent of the stomach in embryologic development. It can be found in about 4.5% of infants and up to 12% of children. Its presence is estimated at around. 1 to 10% in adults. (1) In comparison with Barrett esophagus, which was first described in 1950 by Norman Barrett, the prevalence is not low. However, for most primary care physicians and some gastroenterologists, inlet patch of esophagus is an easily unperceived lesion. It has not gotten much attention since first being described in 1805. Currently, fewer than 50 articles related to inlet patch have been published in MEDLINE.

Inlet patch is easily overlooked on endoscopic examination, due to its location. One study found that the rate of diagnosis by operators who were studying the prevalence of inlet patch was 10 times greater than operators who were unaware of the study. (2) Another reason for the low rate of diagnosis is due to decreased clinical importance and the subsequent lack of information available in the textbooks. In addition, as there is little chance of malignant transformation, this lesion is frequently overlooked, or given low priority. Approximately 25 cases of adenocarcinoma related to inlet patch have been reported. Most of the time, it appears as a benign incidental finding at endoscopy such as erosions, ulcerations, cystic dilations of the glands, fibrosis, intestinal metaplasia or angiodysplasia.

In this issue of the Southern Medical Journal, Chong et al report 5 cases of esophageal inlet patch presenting with various laryngeal and oropharyngeal symptoms, ranging from asymptomatic to protracted symptoms such as chronic cough. (3) According to previous reports, oxyntic mucosa was the most common histologic type, followed by cardiac mucosa. Theoretically, laryngeal, oropharyngeal and bronchial symptoms should be common because of the acid secretion from inlet patch. (4-6) Also, there is an obvious relation among nonerosive reflux disorder, functional heartburn, gastroesophageal reflux disease and inlet patch. Unfortunately, there is not enough evidence concerning these topics. Further studies are needed to help define the role and clinical significance of the inlet patch in these fields.

Another issue needing to be addressed is its relation with Barrett esophagus. Traditionally, Barrett esophagus is considered a distinct entity from esophageal inlet patch. Barrett esophagus is an acquired precancerous lesion and the cell origin probably involves multipotential undifferentiated cells. Inlet patch is considered to be congenital and has no malignant potential. However, recent studies have challenged these concepts. More and more endoscopic series have demonstrated a frequent association of cervical inlet patch with Barrett esophagus. Up to half of all patients with cervical inlet patch have concurrent Barrett esophagus in some reports. (7) Immunohistologic studies reveal a similarity between Barrett epithelium and inlet patch. These studies indicate that they have the same mucin core protein expression and cytokeratin pattern, suggesting a pathogenetic link between these two diseases. (8-10) Based on these important findings and an increasing awareness, we expect to see more studies on inlet patch in the near future.

References

1. Bohman-Manesh F, Farnum JB. Incidence of heterotopic gastric mucosa in the upper oesophagus. Gut 1991;32:968-972.

2. Maconi G, Pace F, Vago L, et al. Prevalence and clinical features of heterotopic gastric mucosa in the upper oesophagus (inlet patch). Eur J Gastroenterol Hepatol 2000;12:745-749.

3. Chong VH, Jalihal A. Cervical Inlet Patch: Case Series and Literature Review. South Med J 2006;99:865-869.

4. Macha S, Reddy S, Rabah R, et al. Inlet patch: heterotopic gastric mucosa-another contributor to supraesophageal symptoms? J Pediatr 2005;147:379-382.

5. Silvers WS, Levine JS, Poole JA, et al. Inlet patch of gastric mucosa in upper esophagus causing chronic cough and vocal cord dysfunction. Ann Allergy Asthma Immunol 2006;96:112-115.

6. Akbayir N, Sokmen HM, Calis AB, et al. Heterotopic gastric mucosa in the cervical esophagus: could this play a role in the pathogenesis of laryngopharyngeal reflux in a subgroup of patients with posterior laryngitis? Scand J Gastroenterol 2005;40:1149-1156.

7. Sontag SJ, Schnell T, Chejfec G, et al. Barrett's esophagus is found in half of all patients with cervical inlet patch. Gastroenterology 1999;116:A316.

8. Malhi-Chowla N, Ringley RK, Wolfsen HC. Gastric metaplasia of the proximal esophagus associated with esophageal adenocarcinoma and Barrett's esophagus: what is the connection? Inlet patch revisited. Dig Dis 2000;18:183-185.

9. Avidan B, Sonnenberg A, Chejfec G, et al. Is there a link between cervical inlet patch and Barrett's esophagus? Gastrointest Endosc 2001;53:717-721.

10. Lauwers GY, Mino M, Ban S, et al. Cytokeratins 7 and 20 and mucin core protein expression in esophageal cervical inlet patch. Am J Surg Pathol 2005;29:437-442.

Chung-Wang Ko, MD, and Chi-Sen Chang, MD

From the Division of Gastroenterology, Taichung Veterans General Hospital, Taichung; the Department of Internal Medicine, National Yang-Ming University, Taipei; and the Institute of Medicine, Chung-Shan Medical University, Taichung, Taiwan.

Reprint requests to Dr. Chi-Sen Chang, Chief, Endoscopy Unit, Department of Gastroenterology & Hepatology, Taichung Veterans General Hospital, Taichung City 40705, Taiwan. Email: [e-mail]

Accepted April 10, 2006.