Esophagus
Nonneoplastic disorders
Epidermoid metaplasia

Author: Yukihiro Nakanishi, M.D., Ph.D.
Editorial Board Member Review: Raul S. Gonzalez, M.D.
Editor-in-Chief Review: Debra Zynger, M.D.

Revised: 19 November 2018, last major update October 2018

Copyright: (c) 2018, PathologyOutlines.com, Inc.

PubMed Search: Esophagus[TIAB] (epidermization OR epidermoid metaplasia OR esophageal leukoplakia OR orthokeratosis OR hyperkeratosis)

Cite this page: Nakanishi, Y. Epidermoid metaplasia. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/esophagusepidermization.html. Accessed December 12th, 2018.
Definition / general
  • Esophageal squamous epithelium with a prominent granular layer and orthokeratosis / hyperorthokeratosis, resembling the epidermis of the skin
Essential features
  • Affects middle aged to elderly individuals with a history of smoking and alcohol intake
  • Well demarcated white plaque in the mid to distal esophagus
  • Esophageal squamous epithelium with a prominent granular layer and orthokeratosis / hyperorthokeratosis
  • Possible association with esophageal squamous cell carcinoma and dysplasia
  • Follow up unless a patient has a concurrent squamous cell carcinoma
Terminology
  • Also known as epidermization, esophageal leukoplakia, orthokeratosis and hyperkeratosis
ICD coding
  • K22.9: Disease of esophagus, unspecified
Epidemiology
Sites
Etiology
Clinical features
  • Dysphagia or asymptomatic
  • Endoscopy findings
    • Scaly or shaggy white plaque with clear borders
    • Mimics crackleware china
    • Lugol voiding lesion with clear demarcation, resembling superficial esophageal cancer (Hepatogastroenterology 2011;58:809)
Diagnostic criteria
  • Esophageal squamous epithelium with a prominent granular layer and orthokeratosis / hyperorthokeratosis, resembling the epidermis of the skin
Case reports
Treatment
  • Follow up unless a patient has a concurrent squamous cell carcinoma
Clinical images

Images hosted on other servers:

Scaly white plaque

Gross description
Microscopic (histologic) description
  • Esophageal squamous epithelium with a compact layer of orthokeratosis / hyperorthokeratosis and a prominent granular layer 1 - 4 cells thick with keratohyalin granules, resembling the epidermis of the skin
  • Abrupt transition from the adjacent normal squamous epithelium
Microscopic (histologic) images

Images hosted on PathOut server:

Contributed by Yukihiro Nakanishi, M.D., Ph.D.

Orthokeratosis /
hyperorthokeratosis

Prominent granular layer

Positive stains (IHC and special stains)
Molecular / cytogenetics description
  • Targeted next generation sequencing analysis of epidermoid metaplasia showed frequently mutated genes consisted of TP53, PIK3CA, EGFR, MYCN, HRAS and the TERT promoter (Mod Pathol 2017;30:1613)
Differential diagnosis
  • Hyperkeratosis: no prominent granular layer
  • Parakeratosis: nuclei present in a keratin layer without an associated prominent granular layer
  • Dysplasia: variable nuclear atypia present
  • Squamous cell carcinoma in situ: full thickness nuclear atypia present
  • Atrophic change: no orthokeratosis or prominent granular layer
Additional references
Board review question #1
Which of the following statements about epidermization / epidermoid metaplasia of the esophagus is false?

  1. Associated with smoking and excessive alcohol consumption
  2. Characterized by orthokeratosis / hyperorthokeratosis and a prominent granular layer
  3. PAS stain highlights epidermoid metaplasia
  4. Surrounding background mucosa should be examined carefully due to possible association with squamous cell carcinoma and dysplasia
Board review answer #1
C. PAS stain shows reduced expression of PAS+ cells compared with normal squamous epithelium, leading to Lugol voiding lesion with clear demarcation, resembling superficial esophageal cancer.
Board review question #2
Which of the following statements about histologic features of epidermization / epidermoid metaplasia of the esophagus is true?



  1. Characterized by the presence of the stratum lucidum beneath the cornified layer
  2. Finding of increased thickness in the cornified layer is called parakeratosis
  3. Granular layer is characterized by the presence of basophilic stained granules known as keratohyalin granules
  4. Orthokeratosis / hyperkeratosis is more frequently seen in the esophagus than parakeratosis
Board review answer #2
C. Epidermization / epidermoid metaplasia is histopathologically characterized by the presence of the granular layer beneath the cornified layer. The granular layer contains basophilic stained granules known as keratohyalin granules. Parakeratosis is characterized by keratosis with persistence of the cell nuclei. The stratum lucidum is seen only in soles and palms and is not seen in epidermization / epidermoid metaplasia. Parakeratosis is more frequently seen in the esophagus than orthokeratosis / hyperkeratosis.

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