Definition/General
Introduction:
Umbilical cord stricture represents a focal narrowing of the umbilical cord diameter
It occurs due to localized compression or developmental abnormality
The stricture involves all cord components including vessels and Wharton jelly
It can lead to fetal compromise and adverse outcomes.
Origin:
Originates from developmental anomalies during cord formation
Results from localized pressure effects during gestation
May be associated with cord entanglement or compression
Can develop from inflammatory processes affecting cord structure
Associated with vascular compromise and reduced blood flow.
Classification:
Classified as congenital or acquired strictures
Mild stricture (minimal diameter reduction)
Moderate stricture (significant narrowing)
Severe stricture (marked constriction with vascular compromise)
Multiple strictures may occur along cord length.
Epidemiology:
Rare condition occurring in 0.1-0.5% of pregnancies
More common with advanced maternal age
Associated with oligohydramnios
Higher incidence in multiple gestations
Male fetuses show slightly higher predisposition
Risk increases with cord entanglement and abnormal presentations.
Clinical Features
Presentation:
Fetal growth restriction (most common presentation)
Abnormal fetal heart rate patterns
Oligohydramnios in severe cases
Reduced fetal movements reported by mother
Abnormal Doppler studies showing increased resistance
May present as intrauterine fetal demise in severe cases.
Symptoms:
Maternal perception of decreased fetal movement
Abnormal non-stress test results
Variable decelerations during monitoring
Growth discordance in multiple gestations
Maternal anxiety due to reduced fetal activity
Preterm labor may occur in severe cases.
Risk Factors:
Advanced maternal age (>35 years)
Oligohydramnios throughout pregnancy
Multiple gestation pregnancies
Cord entanglement or true knots
Maternal diabetes mellitus
Intrauterine infections
Previous history of cord abnormalities
Genetic syndromes affecting connective tissue.
Screening:
Routine ultrasonography during second and third trimesters
Doppler studies of umbilical vessels
Biophysical profile assessment
Non-stress testing in third trimester
Amniotic fluid volume assessment
Fetal growth monitoring with serial measurements.
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Gross Description
Appearance:
Focal narrowing of umbilical cord with visible constriction
Pale or discolored area at stricture site
Normal cord diameter proximal and distal to stricture
Reduced cord circumference at affected area
May show surface irregularities or grooves.
Characteristics:
Firm consistency at stricture site compared to normal cord
Smooth or irregular surface depending on cause
Color may range from pale to gray-white
Visible vessel compression within stricture
Surrounding cord may appear normal or swollen.
Size Location:
Stricture length varies from 0.5-5 cm
Can occur anywhere along cord length
Mid-cord location most common
May be multiple strictures in severe cases
Diameter reduction ranges from 20-80% of normal cord diameter.
Multifocality:
Single stricture in majority of cases (80-90%)
Multiple strictures in 10-20% of cases
May be associated with other cord abnormalities
Segmental involvement possible in severe cases
Can occur with cord knots or entanglement.
Microscopic Description
Histological Features:
Compressed Wharton jelly with reduced mucopolysaccharide content
Vascular compression affecting all three vessels
Reduced vessel lumen diameter
Smooth muscle hypertrophy in vessel walls
Fibrosis may be present in chronic cases.
Cellular Characteristics:
Compressed fibroblasts within Wharton jelly matrix
Endothelial flattening in compressed vessels
Smooth muscle cell changes in arterial walls
Inflammatory infiltrate may be present
Collagen deposition in chronic strictures.
Architectural Patterns:
Concentric compression pattern affecting all cord components
Asymmetric involvement possible with external pressure
Vessel wall thickening with luminal narrowing
Wharton jelly condensation around vessels
Fibrotic bands may be present in severe cases.
Grading Criteria:
Mild stricture (10-30% diameter reduction, minimal vascular compromise)
Moderate stricture (30-60% reduction, moderate vascular changes)
Severe stricture (>60% reduction, significant vascular compromise)
Assessment includes vessel patency and tissue viability.
Immunohistochemistry
Positive Markers:
Smooth muscle actin highlights vessel walls
CD31 demonstrates endothelial integrity
Collagen IV shows basement membrane preservation
Vimentin stains fibroblasts in Wharton jelly
Desmin positive in smooth muscle cells.
Negative Markers:
Cytokeratin typically negative in normal cord tissue
S-100 negative (helps exclude neural tissue)
CD68 negative unless inflammatory infiltrate present
Trichrome stain may show increased collagen in chronic cases.
Diagnostic Utility:
IHC helps assess vessel integrity and patency
Confirms endothelial viability in compressed vessels
Demonstrates smooth muscle preservation or loss
Helps identify inflammatory components
Useful for assessing tissue viability at stricture site.
Molecular Subtypes:
Assessment focuses on vascular integrity markers
Hypoxia markers (HIF-1α) may be positive
Apoptosis markers (TUNEL, caspase-3) in severe cases
Proliferation markers (Ki-67) typically low
Angiogenesis markers (VEGF) may be elevated.
Molecular/Genetic
Genetic Mutations:
Usually non-genetic developmental anomaly
Associated with connective tissue disorders in rare cases
Collagen gene mutations may predispose to stricture formation
Vascular development genes may be involved
Extracellular matrix genes affect Wharton jelly composition.
Molecular Markers:
Hypoxia-inducible factors may be elevated
Matrix metalloproteinases involved in tissue remodeling
Growth factors (PDGF, TGF-β) affect vessel development
Collagen synthesis markers may be altered
Apoptosis pathways activated in severe compression.
Prognostic Significance:
Severity of stricture correlates with fetal outcomes
Vascular compromise predicts growth restriction
Location and multiplicity affect prognosis
Associated anomalies worsen outcomes
Gestational age at diagnosis influences management.
Therapeutic Targets:
Management focuses on fetal monitoring and timely delivery
Doppler surveillance of fetal vessels
Growth assessment and biophysical profile monitoring
Steroid administration for fetal lung maturity
Delivery planning based on severity and gestational age.
Differential Diagnosis
Similar Entities:
Umbilical cord knots (true or false knots with different morphology)
Cord hematoma (localized bleeding with different gross appearance)
Cord tumors (hemangioma, teratoma with distinct histology)
Cord torsion (spiral pattern, different mechanism)
Velamentous insertion (different location and pattern).
Distinguishing Features:
Cord stricture: focal narrowing with smooth transition
Cord stricture: concentric compression pattern
Cord knots: looped configuration with crossing vessels
Cord hematoma: hemorrhage and blood products
Cord tumors: mass lesion with specific tissue types
Torsion: spiral configuration with rotational changes.
Diagnostic Challenges:
Distinguishing from normal cord variations in diameter
Differentiating from artificial compression during processing
Identifying multiple strictures along cord length
Assessing functional significance of mild strictures
Correlating morphology with clinical findings.
Rare Variants:
Segmental stricture involving long cord segments
Multiple strictures with intervening normal cord
Progressive stricture developing during pregnancy
Inflammatory stricture secondary to infection
Post-procedure stricture following interventions.
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
Umbilical cord measuring [length] cm with focal stricture at [location]
Diagnosis
Umbilical cord stricture
Severity Classification
Severity: [mild/moderate/severe] with [percentage]% diameter reduction
Histological Features
Shows [degree] compression of Wharton jelly with [vascular changes]
Location and Extent
Located at [distance] cm from [fetal/placental] insertion, extending [length] cm
Vascular Assessment
Umbilical vessels show [degree] of compression with [patency status]
Associated Findings
Associated findings: [list any additional abnormalities]
Clinical Correlation
Clinical history of [symptoms/findings] correlates with [severity] of stricture
Prognostic Factors
Risk factors for fetal compromise: [list relevant factors]
Final Diagnosis
Umbilical cord stricture, [severity grade], with [clinical significance]