Pathology of esophagus

A) Developmental Malformations

Atresia: failure of embryonal canalization

Tracheoesophageal fistula (TEF)

• Common congenital abnormality; abnormal connection between esophagus and trachea due to failure of proper division during embryological development
• Most common form: upper esophageal segment ends in a blind pouch + lower segment communicates with the trachea
• Consequences: swallowing → food → trachea → choking, coughing, vomiting, cyanosis; breathing → air → stomach → ballooning

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B) Anatomical and Motor Disorders

Diverticula (outpouchings of esophageal wall)

• Traction diverticula: pulled from outside (e.g. fibrous adhesions)
• Pulsion diverticula: pushed from inside (e.g. high luminal pressure)
• Locations:
  • Upper esophagus (pharyngeal mucosa): Zenker’s diverticulum
  • Esophageal body: traction diverticulum (TB lymph node scarring)
  • Lower esophagus: epiphrenic pulsion diverticulum (associated with hernia, GERD, achalasia)
• Consequences: food accumulation → nocturnal regurgitation + aspiration pneumonia

Achalasia

• Functional disorder characterized by:
  • Esophageal aperistalsis
  • Incomplete/partial relaxation of LES in response to swallowing
  • Increased LES tone
• Causes: Primary = loss of intrinsic inhibitory innervation of LES; Secondary = idiopathic (e.g. diabetic autonomic neuropathy)
• Consequences: megaesophagus (progressive dilation above LES), inflammation, ulceration, mucosal thickening
• Clinical: progressive dysphagia, nocturnal regurgitation, aspiration of undigested food; risk for esophageal SCC

Hiatal Hernia (hernia diaphragmatica)

• Upper part of stomach protrudes into the thorax through a weakness in the diaphragm
• Sliding hernia: gastroesophageal junction moves above diaphragm → ball-shaped dilation
• Paraesophageal hernia: portion of stomach (greater curvature) rolls into thorax
• Symptoms: heartburn, dysphagia, pain when swallowing
• Congenital: posterolateral defect → abdominal organs in thorax → dyspnea + cyanosis in newborn (lung hypoplasia)

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C) Inflammation (Esophagitis)

GERD (Gastroesophageal Reflux Disease)

• Reflux of gastric juice into esophagus due to LES incompetence
• Consequences:
  • Mucosal injury → inflammation, necrosis, ulceration → granulation tissue → fibrosis/stenosis → stricture
  • Keratinization → leukoplakia
  • Barrett’s esophagus: chronic reflux → replacement of distal stratified squamous epithelium by metaplastic columnar epithelium containing goblet cells; endoscopically = reddish patches extending upward from GEJ; affects males 40–60 years old; dysplasia → risk for esophageal adenocarcinoma
• Clinical: heartburn, dysphagia, regurgitation of sour-tasting content; occasionally chest pain (may mimic MI)

Infective Esophagitis (Candidiasis)

• Antibiotics, DM, malignancy, immunocompromised
• White adherent mucosal patches + painful/difficult swallowing

Mallory-Weiss Syndrome (Lacerations)

• Longitudinal tears at the gastroesophageal junction
• Seen in chronic alcoholics (severe vomiting); also acute illness with severe vomiting
• Pathogenesis: insufficient LES relaxation during vomiting → tearing during propulsive expulsion
• Complication: GI bleeding

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D) Esophageal Varices

• Portal hypertension (e.g. cirrhosis) → porto-caval anastomoses → portal blood → gastric veins → esophageal subepithelial/submucosal plexus (→ azygous vein → IVC)
• Portal HTN → dilation of tortuous veins (varices) in esophageal plexus
• Variceal rupture → hematemesis, melena, hemorrhagic shock and death

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E) Esophageal Tumors

Adenocarcinoma

• In association with Barrett’s esophagus → dysplasia
• Risk ↑ with tobacco, obesity, radiation therapy; degree of dysplasia is strongest predictor of progression
• Location: distal third of esophagus
• Morphology: flat patches → large exophytic masses; may infiltrate/ulcerate; micro = mucin-producing adenocarcinoma
• Complications: mechanical obstruction → cachexia; tracheoesophageal fistula; ichorous mediastinitis
• Poor prognosis

Squamous Cell Carcinoma

• Males >50 years; alcohol + tobacco
• Progresses: dysplasia → carcinoma in situ → invasive cancer
• Location: middle third of esophagus (50%)
• Morphology: grey-white plaque-like thickenings → large obstructing masses → ulcerative/infiltrative
• Clinical: progressive dysphagia (solid → liquid diet)
• Prognosis: 5-year survival = 5% if lymph node metastasis present at resection

💡 High-yield: Zenker’s = upper esophagus pulsion diverticulum. Achalasia = aperistalsis + incomplete LES relaxation + SCC risk. Barrett’s = goblet cell metaplasia from chronic GERD → adenocarcinoma risk. Mallory-Weiss = alcoholic vomiting → longitudinal tears → GI bleed. Varices = portal hypertension → fatal rupture. Esophageal SCC = middle third; alcohol/tobacco; 5% 5-yr survival with LN mets.