Definition/General
Introduction:
Umbilical cord torsion refers to excessive twisting of the umbilical cord around its longitudinal axis
Normal cords have 1 twist per 5 cm of cord length
Hypertorsion (>1 twist per 3 cm) and hypotorsion (<1 twist per 6 cm) are pathological
It can cause vascular compromise and fetal complications.
Origin:
Results from excessive fetal movement in utero
May be caused by oligohydramnios or fetal position abnormalities
Genetic factors may predispose to abnormal coiling
Associated with cord length abnormalities
Uterine anomalies may contribute.
Classification:
Classified as hypertorsion (excessive twisting) or hypotorsion (insufficient twisting)
Left-handed coiling (sinistral) versus right-handed coiling (dextral)
Segmental torsion versus entire cord involvement
Acute versus chronic torsion.
Epidemiology:
Abnormal coiling occurs in 5-15% of pregnancies
Hypertorsion more common than hypotorsion
Associated with increased perinatal morbidity
More frequent in male fetuses
No specific maternal age predilection.
Clinical Features
Presentation:
Fetal distress during labor
Variable decelerations on monitoring
Intrauterine growth restriction (IUGR)
Oligohydramnios
Decreased fetal movements
Meconium-stained liquor.
Symptoms:
Abnormal fetal heart rate patterns
Bradycardia or tachycardia
Cord compression signs
Emergency cesarean section indication
Stillbirth in severe cases
Neonatal complications.
Risk Factors:
Oligohydramnios
Fetal growth restriction
Male fetal gender
Advanced gestational age
Excessive fetal movement
Uterine anomalies.
Screening:
Ultrasound assessment of cord coiling
Color Doppler evaluation
Umbilical artery flow studies
Amniotic fluid volume assessment
Fetal monitoring during labor.
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Gross Description
Appearance:
Excessively twisted or straight cord appearance
Tight coiling in hypertorsion
Minimal spiraling in hypotorsion
May show areas of constriction
Color changes from vascular compromise.
Characteristics:
Focal narrowing at twisted segments
Vessel congestion may be visible
Edema distal to constriction
Hemorrhage may be present
Cord may appear indurated or soft.
Size Location:
May involve entire cord length or focal segments
Measurement of coiling index important
Site of maximum torsion identification
Cord length assessment
Placental insertion evaluation.
Multifocality:
Usually involves entire cord
May have focal areas of extreme torsion
Segmental variations in coiling
Associated with cord length abnormalities.
Microscopic Description
Histological Features:
Compressed vessels with altered morphology
Vascular congestion or collapse
Thrombosis may be present
Wharton's jelly compression or edema
Inflammatory changes possible.
Cellular Characteristics:
Endothelial damage in compressed vessels
Smooth muscle degeneration possible
Fibroblast changes in Wharton's jelly
Inflammatory infiltrate if severe
Red blood cell extravasation.
Architectural Patterns:
Vessel distortion and compression
Altered vessel wall architecture
Perivascular edema or fibrosis
Loss of normal spiral arrangement
Focal areas of necrosis possible.
Grading Criteria:
Assessment of coiling index
Vessel compression degree
Thrombosis presence
Inflammatory response severity
Tissue necrosis extent.
Immunohistochemistry
Positive Markers:
CD31 highlights vessel endothelium
CD34 in vascular walls
Smooth muscle actin in vessel walls
Factor VIII in endothelium
Fibrin stains if thrombosis present.
Negative Markers:
Cytokeratin negative in vessels
No specific negative markers required
Normal vascular immunophenotype expected
Inflammatory markers variable.
Diagnostic Utility:
Assesses vessel integrity
Identifies areas of endothelial damage
Confirms thrombosis if present
Evaluates tissue viability
Research applications.
Molecular Subtypes:
No specific molecular classification
Hypoxia markers may be elevated
Inflammatory mediators present
Apoptosis markers in severe cases.
Molecular/Genetic
Genetic Mutations:
No specific genetic mutations identified
Connective tissue gene variants possible
Vascular development genes may be involved
Possible familial clustering
Collagen synthesis abnormalities.
Molecular Markers:
Hypoxia-inducible factors upregulated
Inflammatory mediators elevated
Stress response proteins
Apoptosis markers in severe cases
Vascular remodeling factors.
Prognostic Significance:
Severe torsion associated with poor outcomes
Hypertorsion more significant than hypotorsion
IUGR and fetal distress common
Increased cesarean section rate
Neonatal complications possible.
Therapeutic Targets:
No specific therapeutic interventions
Enhanced monitoring during labor
Delivery timing optimization
Neonatal resuscitation preparedness
Future pregnancy counseling.
Differential Diagnosis
Similar Entities:
Normal cord coiling
Cord compression from other causes
Cord prolapse
Nuchal cord
Cord entanglement.
Distinguishing Features:
Torsion: excessive twisting pattern
Torsion: abnormal coiling index
Normal: regular spiral pattern
Compression: external pressure
Prolapse: cord ahead of presenting part
Nuchal: cord around neck.
Diagnostic Challenges:
Coiling index calculation
Distinguishing from normal variation
Clinical correlation importance
Measurement standardization
Postmortem changes consideration.
Rare Variants:
Complete cord torsion with vessel occlusion
Segmental torsion
Torsion with cord rupture
Multiple site torsion
Torsion in multiple pregnancy.
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 [X] cm in length
Coiling Assessment
Coiling pattern: [left/right-handed], coiling index: [X] twists per cm
Coiling Classification
Classification: [normal/hypertorsion/hypotorsion] based on coiling index
Vessel Examination
Vessels: [normal/compressed/congested], [present/absent] thrombosis
Areas of Maximum Torsion
Maximum torsion at: [location], with [degree] of vessel compromise
Microscopic Findings
Microscopy shows [normal/abnormal] vessel architecture with [present/absent] compression effects
Clinical Significance
Clinical significance: [risk assessment] for fetal complications
Final Diagnosis
Umbilical cord [hypertorsion/hypotorsion], coiling index [X]