Primary Motility  Disorders of the  Esophagus
 The Esophageal
 Mucosa
 The
 Esophagogastric  Junction
 Barrett's
 Esophagus

  Browse by Author
  Browse by Movies
OESO©2015
 
Volume: Barrett's Esophagus
Chapter: Diagnosis
 

What is the significance of the "distinctive cell" at the junction of squamous and Barrett's epithelium? In what proportion of junctional biopsies is it found?

D.A. Antonioli (Boston)

Barrett's esophagus represents the metaplastic conversion of distal esophageal squamous epithelium to a glandular phenotype in some patients as a result of injury, ulceration, and repair in an abnormal milieu (typically, an acidic environment). The cell giving rise to Barrett's esophagus has not yet been clearly identified. However, experimental and clinical observations support the premise that Barrett's esophagus arises from a multipotential stem cell within the esophagus rather than from the upward growth of glandular tissue from the proximal stomach. The main candidates for this multipotential stem cell are the basal cell of the squamous mucosa and cells lining the ducts of the esophageal mucous glands [1-3].

If the theory proposed above is correct, it is possible to postulate that various stages of conversion from a squamous to a glandular phenotype might be detected in the morphologic evaluation of Barrett's esophagus. Supporting this notion is the detection of the so-called "distinctive cell". This is a cuboidal to low columnar cell that is located at the junction of squamous mucosa and Barrett's esophagus. When examined by scanning electron microscopy, these cells exhibit apical surface features characteristic of both squamous and glandular epithelia: intercellular ridges and focal surface microridges (normal features of squamous cells) and microvilli (a characteristic of columnar glandular cells) [4-6]. Of interest, these scanning electron microscopic features are identical to those present on the surface of the cervical transformation zone, which is an area of physiologic epithelial metaplasia in which glandular mucosa becomes squamified under hormonal influences beginning at menarche. When examined by transmission electron microscopy examination, the distinctive cells contain surface microvilli, an abortive apical glycocalyx and numerous vesicles, some containing secretory material, in the apical cytoplasm [6].

The distinctive cells are interdigitated among normal squamous and glandular cells, and they appear to be unique to Barrett's esophagus. In a recent study, distinctive cells were detected at the squamous-glandular junction in 38% of Barrett's esophagus patients but in none of the patients without Barrett's esophagus and with a normal squamocolumnar junction located at the gastroesophageal junction [6]. Thus, the distinctive cell most likely represents an intermediate stage in squamous-glandular metaplasia. Its relationship to the recently described "multilayered epithelium", which is likely another manifestation of metaplasia in Barrett's esophagus, has not yet been explored [7].

References

1. Berenson MM, Johnson TD, Markowitz NR, et al. Restoration of squamous mucosa after ablation of Barrett's esophageal epithelium. Gastroenterology 1993;104:1686-1691.

2. Feule GE, Helmstaedter V, Buehring A, et al. Distinct immunohistochemical findings in columnar epithelium of esophageal inlet patch and of Barrett's esophagus. Dig Dis Sci 1990;35:86-92.

3. Levine DS, Rubin CE, Reid BJ, Haggitt RC. Specialized metaplastic columnar epithelium in Barrett's esophagus: a comparative transmission electron microscopic study. Lab Invest 1989;60:418-432.

4. Shields HM, Zwas F, Antonioli DA, et al. Detection by scanning electron microscopy of a distinctive esophageal surface cell at the junction of squamous and Barrett's epithelium. Dig Dis Sci 1993;38:97-108.

5. Shields HM, Sawhney RA, Zwas F, et al. Scanning electron microscopy of the human esophagus: application to Barrett's esophagus, a precancerous lesion. Microsc Res Tech 1995;31:248-256.

6. Sawhney RA, Shields HM, Allan CH, et al. Morphological characterization of the squamocolumnar junction of the esophagus in patients with and without Barrett's epithelium. Dig Dis Sci 1996;41:1088-1098.

7. Boch JA, Shields HM, Antonioli DA, et al. Distribution of cytokeratin markers in Barrett's specialized columnar epithelium. Gastroenterology 1997;112:760-765.


Publication date: August 2003 OESO©2015