Definition/General
Introduction:
Normal colonic cytology demonstrates characteristic features of healthy colonic mucosa
Understanding normal patterns is essential for recognizing pathological changes
Colonic cytology obtained through brushing, washing, or FNA.
Origin:
Colonic mucosa lined by simple columnar epithelium
Surface absorptive cells and goblet cells
Crypts of Lieberkühn extend to muscularis mucosae
No villi in normal colon.
Classification:
Normal colonic cells by location and function
Surface absorptive cells: Tall columnar with brush border
Goblet cells: Mucin-producing
Crypt base cells: Stem cells and Paneth cells.
Epidemiology:
Normal colonic cytology shows minimal regional variation
Age-related changes
Microbiome influences
Dietary factors affect morphology.
Clinical Features
Presentation:
Asymptomatic individuals
Screening procedures
Surveillance colonoscopy
Research studies
Quality control specimens.
Symptoms:
No symptoms in normal individuals
Normal bowel movements
No abdominal pain
No bleeding
Normal appetite.
Risk Factors:
No specific risk factors
Age-related changes
Dietary influences
Environmental factors
Genetic variations.
Screening:
Colorectal cancer screening
Family history screening
IBD surveillance
High-risk populations.
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Gross Description
Appearance:
Pink, smooth mucosa
Normal haustral pattern
No polyps or masses
Regular vascular pattern
Normal caliber.
Characteristics:
Glistening mucosal surface
Subtle fold pattern
Normal peristalsis
Clear luminal contents
No inflammatory changes.
Size Location:
Normal anatomy: Cecum, ascending, transverse, descending, sigmoid colon, rectum
Regional differences in diameter
Smooth muscle walls.
Multifocality:
Uniform appearance throughout
No focal lesions
Normal anatomical landmarks
Physiological variations.
Microscopic Description
Histological Features:
Simple columnar epithelium
Surface absorptive cells: Tall columnar, basally located nuclei
Goblet cells: Scattered, mucin-filled
Straight crypts
Regular architecture.
Cellular Characteristics:
Absorptive cells: 25-30 μm height, oval basal nuclei, prominent brush border
Goblet cells: Variable sizes, apical mucin, basal nuclei
Uniform nuclear features.
Architectural Patterns:
Surface epithelium continuity
Straight parallel crypts
Normal crypt length
Regular spacing
Intact basement membrane.
Grading Criteria:
Adequate cellularity: Representative surface and crypt cells
Good preservation: Clear morphology
Clean background: Minimal debris.
Immunohistochemistry
Positive Markers:
CK20 (surface gradient)
CDX2 (intestinal differentiation)
Villin (brush border)
MUC2 (goblet cells)
Ki-67 (crypt base only).
Negative Markers:
CK7 (upper GI)
CK5/6 (squamous)
p63 (squamous)
Chromogranin (neuroendocrine).
Diagnostic Utility:
Confirms colonic epithelial identity
Normal differentiation markers
Proliferation assessment
Reference standard.
Molecular Subtypes:
Normal colonic phenotype
Regional variations
Age-related changes
No pathological subtypes.
Molecular/Genetic
Genetic Mutations:
No pathological mutations
Normal DNA repair
Intact APC pathway
Normal p53 function.
Molecular Markers:
Normal Wnt signaling
Intact p53 pathway
Normal proliferation control
Stable microsatellites.
Prognostic Significance:
Baseline normal state
Reference for comparison
No malignant potential
Quality standard.
Therapeutic Targets:
No treatment required
Preventive screening
Lifestyle modifications
Dietary recommendations.
Differential Diagnosis
Similar Entities:
Reactive changes
Hyperplastic polyp
Mild dysplasia
Inflammatory changes
Regenerative atypia.
Distinguishing Features:
Normal: Regular architecture
Normal: No nuclear atypia
Reactive: Nuclear enlargement
Hyperplastic: Serrated architecture
Dysplasia: Nuclear stratification.
Diagnostic Challenges:
Sampling adequacy
Processing artifacts
Age-related changes
Technical variations.
Rare Variants:
Paneth cell metaplasia
Gastric metaplasia
Squamous metaplasia.
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
Colonic cytology, [technique used], adequate cellularity
Diagnosis
Normal colonic cytology
Cellular Composition
Normal colonic epithelium: [absorptive cells] and [goblet cells]
Morphological Features
Shows [typical columnar cells] with [normal nuclear features]
Goblet Cells
Goblet cells: [present in normal proportion]
Nuclear Features
Nuclear features: [regular, basally located, uniform chromatin]
Background Findings
Background: [clean], [mucus], no inflammation
Adequacy Assessment
Specimen adequacy: [satisfactory for evaluation]
Final Diagnosis
Colonic cytology: Within normal limits