Definition/General
Introduction:
Esophageal diverticulum represents outpouching of esophageal wall creating a pouch-like structure
Classified based on anatomical location and underlying mechanism
True diverticula involve all wall layers
False diverticula involve only mucosa and submucosa
Most common types are Zenker (pharyngoesophageal), traction (mid-esophageal), and epiphrenic (distal).
Origin:
Pulsion diverticula result from increased intraluminal pressure
Traction diverticula result from external inflammatory adhesions
Zenker diverticula develop at Killian's triangle (weakness between cricopharyngeus and inferior constrictor)
Mid-esophageal diverticula often secondary to mediastinal inflammation
Epiphrenic diverticula associated with motility disorders.
Classification:
Zenker diverticulum (pharyngoesophageal junction)
Traction diverticulum (mid-esophagus)
Epiphrenic diverticulum (distal esophagus)
True diverticula (all layers) vs false diverticula (mucosa/submucosa only)
Pulsion type vs traction type based on mechanism.
Epidemiology:
Zenker diverticula most common in elderly (>60 years)
Male predominance (2:1 ratio)
Traction diverticula associated with mediastinal disease
Epiphrenic diverticula rare (<5% of esophageal diverticula)
Higher prevalence in developed countries
Associated with GERD and motility disorders.
Clinical Features
Presentation:
Dysphagia (difficulty swallowing)
Regurgitation of undigested food
Halitosis (bad breath) from food retention
Chronic cough
Aspiration pneumonia recurrent episodes
Weight loss
Gurgling sounds during swallowing
Neck mass (Zenker diverticulum).
Symptoms:
Progressive dysphagia over months to years
Nocturnal regurgitation of food particles
Chronic aspiration symptoms
Voice changes or hoarseness
Substernal chest pain
Early satiety
Nutritional deficiencies
Social embarrassment from halitosis and regurgitation.
Risk Factors:
Advanced age (>60 years for Zenker)
Male gender
Gastroesophageal reflux disease
Esophageal motility disorders
Achalasia
Previous mediastinal inflammation (tuberculosis, histoplasmosis)
Hiatal hernia
Connective tissue disorders.
Screening:
Barium swallow best initial imaging study
Upper endoscopy with caution (perforation risk)
CT scan shows diverticular anatomy
Esophageal manometry evaluates motility
pH monitoring for reflux assessment
Videofluoroscopy for swallowing evaluation.
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Gross Description
Appearance:
Pouch-like outpouching from esophageal wall
Zenker diverticulum: posterior outpouching at cervical level
Traction diverticulum: usually small, conical shape
Epiphrenic diverticulum: large, sac-like structure near GEJ
Smooth internal surface
Variable size from few millimeters to >10 cm.
Characteristics:
Zenker: false diverticulum with mucosa and submucosa only
Traction: true diverticulum with all wall layers
Wide neck vs narrow neck configuration
Food debris and secretions may be retained
Inflammatory changes in chronic cases
Smooth muscle hypertrophy in associated areas.
Size Location:
Zenker: 15-20 cm from incisors, posterior wall
Traction: 25-30 cm from incisors, usually anterolateral
Epiphrenic: within 10 cm of GEJ
Size ranges from 1-15 cm
Multiple diverticula possible but uncommon
Giant diverticula >5 cm diameter.
Multifocality:
Usually solitary diverticulum
Multiple diverticula in <10% of cases
Concurrent esophageal pathology (reflux, motility disorders)
Associated hiatal hernia common
Gastric diverticula occasionally coexistent
Pharyngeal diverticula may be multiple.
Microscopic Description
Histological Features:
True diverticula: all esophageal wall layers present (mucosa, submucosa, muscularis propria, adventitia)
False diverticula: only mucosa and submucosa, muscle layer absent or attenuated
Normal esophageal epithelium lines the diverticular sac
Chronic inflammation may be present
Smooth muscle hypertrophy in neck region.
Cellular Characteristics:
Normal squamous epithelium lining diverticulum
Submucosal glands present and may be hyperplastic
Smooth muscle cells show hypertrophy
Chronic inflammatory cells (lymphocytes, plasma cells) in lamina propria
Fibroblasts and collagen deposition in chronic cases
Normal nerve plexus arrangement.
Architectural Patterns:
Outpouching configuration with neck connecting to main lumen
Preserved tissue architecture within diverticular wall
Submucosal gland hyperplasia common
Muscle layer organization variable
Adventitial fibrosis in traction type
Normal epithelial maturation pattern.
Grading Criteria:
No formal grading system for diverticula
Assessment based on size (small <2 cm, medium 2-5 cm, large >5 cm)
Wall thickness evaluation
Inflammatory changes (none, mild, moderate, severe)
Complications (ulceration, perforation, malignancy - rare).
Immunohistochemistry
Positive Markers:
Cytokeratins (CK5/6, CK14) highlight squamous epithelium
Smooth muscle actin and desmin show muscle layer
S-100 highlights neural elements
CD68 shows macrophages
Vimentin positive in mesenchymal elements
Ki-67 low proliferation index normally.
Negative Markers:
Malignancy markers negative in uncomplicated diverticula
p53 negative (excludes dysplasia)
Neuroendocrine markers negative
Melanoma markers negative
Dysplasia markers negative.
Diagnostic Utility:
Epithelial markers confirm normal squamous lining
Muscle markers distinguish true from false diverticula
Inflammatory markers assess chronic changes
Proliferation markers evaluate for dysplasia
Neural markers assess innervation.
Molecular Subtypes:
Classification based on anatomical location
Pathogenesis (pulsion vs traction)
Wall composition (true vs false)
Associated conditions (motility disorders, reflux)
Complications (uncomplicated vs complicated).
Molecular/Genetic
Genetic Mutations:
No specific mutations associated with diverticula formation
Connective tissue genes may be altered (COL1A1, COL3A1)
Smooth muscle genes expression changes
Matrix metalloproteinase alterations
Age-related changes in tissue structure genes.
Molecular Markers:
Collagen expression patterns altered
Elastin fiber abnormalities
Smooth muscle contractile proteins changes
Growth factors (TGF-β, PDGF)
Inflammatory mediators in chronic cases
Aging markers in tissue.
Prognostic Significance:
Size of diverticulum correlates with symptoms
Location affects treatment options
Associated motility disorders worsen prognosis
Age of patient affects surgical risk
Complications (perforation, bleeding) rare but serious.
Therapeutic Targets:
Surgical repair for symptomatic large diverticula
Endoscopic treatment (diverticulotomy)
Medical management of associated GERD
Dietary modifications
Treatment of motility disorders
Conservative management for small, asymptomatic cases.
Differential Diagnosis
Similar Entities:
Esophageal carcinoma with cavitation
Esophageal duplication cyst
Hiatal hernia
Achalasia with pseudo-diverticulum
Esophageal stricture with upstream dilatation
Mediastinal mass compressing esophagus
Vascular compression.
Distinguishing Features:
Diverticulum: outpouching from main lumen
Diverticulum: normal epithelial lining
Carcinoma: irregular mass with dysplasia/malignancy
Duplication cyst: separate structure not communicating with lumen
Achalasia: diffuse dilatation with food retention
Hernia: stomach herniation into chest.
Diagnostic Challenges:
Distinguishing large diverticulum from hernia
Endoscopic evaluation risks perforation
Biopsy sampling from diverticular wall
Associated pathology (reflux, motility disorders)
Complications assessment (inflammation, ulceration).
Rare Variants:
Giant diverticulum (>10 cm)
Intramural diverticulum
Multiple diverticula (diverticulosis)
Congenital diverticulum
Post-surgical diverticulum
Malignancy arising in diverticulum (extremely rare)
Perforated diverticulum.
Sample Pathology Report
Template Format
Sample Pathology Report
Complete Report: This is an example of how the final pathology report should be structured for this condition.
Specimen Information
Esophageal diverticulum specimen from [location] measuring [size] cm
Clinical History
Patient with [dysphagia/regurgitation/other symptoms] and imaging showing diverticulum
Diverticulum Classification
[Zenker/Traction/Epiphrenic] diverticulum, [true/false] type
Microscopic Findings
Shows [all wall layers/mucosa and submucosa only] with normal epithelial lining
Wall Structure
Wall contains: [mucosa, submucosa, muscle layer, adventitia as applicable]
Epithelial Lining
Lined by normal stratified squamous epithelium without dysplasia
Inflammatory Changes
Inflammation: [absent/mild/moderate/severe] chronic changes
Complications
[None identified/ulceration/perforation/other complications]
Associated Findings
[Reflux changes/motility disorder changes/normal] in adjacent esophagus
Final Diagnosis
Esophageal diverticulum, [type and location], [true/false], [uncomplicated/with complications]