Fetopathology and developmental pathology of the embryo and fetus
Marta Ježová, Josef Feit et al.
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+ Atlas of fetal pathology
+ Congenital malformations
+ Physiological developement of an embryo and fetus, growth and changes of the external shape
+ Congenital malformations and congenital anomalies
+ Basic terminology
+ Etiology of congenital anomalies (CA)
+ Environmental causes of congenital anomalies, congenital infections
+ Rubella
+ Cytomegalovirus
+ Syphilis
+ Toxoplasmosis
+ Diabetes mellitus (DM) and pregnancy
+ Diabetic embryopathy
+ Diabetic fetopathy
+ Genetic causes of congenital malformations
+ Chromosomal abnormalities
+ Down syndrome
+ Klinefelter syndrome
+ Turner syndrome
+ Patau syndrome
+ Edwards syndrome
+ Triploidy
+ Single gene disorders
+ Tuberous sclerosis
+ Miscellaneous malformation syndromes, sequences and associations, unclassified
+ Sirenomelia (Mermaid syndrome)
+ Hydrops fetalis
+ Immune hydrops (erythroblastosis fetalis, hemolytic disease of the newborn)
+ Nonimmune hydrops
+ Hygroma colli cysticum
+ Pierre-Robin sequence
+ Caudal regression syndrome (sacral agenesis)
+ VACTERL association
+ Pathology of twinning
+ Complications of monochorionic diamnionic placentation
+ Chronic twin transfusion syndrome
+ Acute twin-twin transfusion
+ Complications of monochorionic monoamnionic placentation
+ Congenital malformations in twins
+ Chorangiopagus parasiticus (acardius)
+ Pathology of higher multiple gestations: triplets
+ Monsters
+ Monstra duplicia
+ Gemini monochoriati inequales
+ Duplicitas symmetros
+ Asymmetric dual monsters
+ Monstra simplicia
+ Congenital malformations of individual organ systems
+ Congenital malformations of the central nervous system
+ Congenital malformations of the spinal cord
+ Spina bifida
+ Myeloschisis (rachischisis posterior)
+ Congenital malformations of the brain
+ Anencephaly
+ Iniencephaly
+ Encephalocele
+ Arnold-Chiari malformation
+ Disorders of formation of the structures derived from the mediobasal prosencephalon
+ Migration disorders
+ Destructive lesions of fetal brain (disruptions)
+ Porencephaly
+ Hydranencephaly
+ Hydrocephalus
+ Dandy-Walker malformation
+ Intracranial non-neoplastic cysts
+ Arachnoid cyst
+ Neuroepithelial cyst
+ Congenital malformations of the respiratory system
+ Congenital cystic adenomatoid malformation (CCAM)
+ Lobar sequestration
+ Congenital lobar emphysema
+ Pulmonary hyperplasia
+ Pulmonary hypoplasia
+ Congenital pulmonary lymphangiectasia
+ Diaphragm and congenital malformations
+ Congenital malformations of kidneys and efferent urinary tracts
+ Renal agenesis
+ Variations of shape and position of the kidneys
+ Renal cystic disease
+ Infantile polycystic kidneys (ARKPD)
+ Renal dysplasia
+ Adult polycystic kidneys (ADPKD)
+ Autosomal dominant polycystic kidney disease in infant and fetus
+ Lower urinary tract obstruction
+ Posterior urethral valves
+ Congenital tubular renal dysgenesis
+ Urinary bladder
+ Hypospadia
+ Congenital malformations of genital system and somatosexual congenital disorders
+ Somatosexual disorders
+ Somatosexual disorders with normal karyotype
+ Pseudohermaphroditism masculinus
+ Androgen insensitivity syndrome, testicular feminization syndrome, female XY
+ Pseudohermaphroditism femininus
+ Congenital adrenal hyperplasia
+ Somatosexual disorders with pathologic karyotype
+ Congenital malformations of female genitalia
+ Congenital malformations of the internal genitalia
+ Congenital malformations associated with congenital malformations of urinary system
+ Congenital malformations of the vulva
+ Congenital malformations of the male genital organs
+ Cryptorchidism
+ Congenital malformations of penis and scrotum
+ Smith-Lemli-Opitz syndrome (SLOS)
+ Congenital tumors
+ Sacrococcygeal teratoma
+ Congenital cardiac rhabdomyoma
+ Congenital heart defects
+ Defects of heart septum
+ Atrial septal defects
+ Ventricular septal defects
+ AV septal defects
+ Anomalies of the great arteries
+ Transposition of the great arteries
+ Truncus arteriosus
+ Double-outlet right ventricle
+ Malformations of the valves
+ Tricuspid atresia
+ Stenosis and atresia of the mitral valve, the hypoplastic left heart syndrome
+ Stenosis of the pulmonary artery
+ Pulmonary atresia with intact ventricular septum
+ Tetralogy of Fallot
+ Aortic stenosis
+ Malformations of the aortic arch system
+ Persistence of ductus arteriosus
+ Coarctation of the aorta
+ Interruption of the aortic arch
+ Right-sided aortic arch
+ Malformations of the venous system
+ Anomalies of situs and heart position
+ Di George syndrome
+ Congenital malformations of the gastrointestinal tract
+ Oral cavity and the palate
+ Cleft lip and palate
+ Congenital defects of the esophagus
+ Atresia
+ Congenital esophagus stenoses
+ Congenital malformations of the stomach
+ Congenital malformations of the intestines
+ Atresia
+ Malrotation of the intestine
+ Remnants of the omphalomesentric duct
+ Anorectal malformations
+ Duplicatures
+ Defects of the abdominal wall
+ Omphalocele
+ Gastroschisis
+ Limb-body wall complex
+ Pentalogy of Cantrell
+ Developemental anomalies of the skeleton
+ Defects of growth of tubular bone and/or spine
+ Thanatophoric dysplasia
+ Diastrophic dysplasia
+ Abnormalities of density of cortical diaphyseal structure or metaphyseal modeling
+ Osteogenesis imperfecta
+ Limb malformations
+ Terminal transverse limb defects
+ Radial ray defects
+ Finger anomalies
+ Club foot
+ Constriction (amniotic) band syndrome
+ Placental inflammation
+ Ascending infections
+ Placental inflammation, acute
+ Hematogenous infections
+ Fetomaternal listeriosis
+ Pathology of the fetal membranes
+ Amniotic band syndrome
+ Meconium staining
+ Candida infection of the placenta
+ Pathology of the placenta
+ Normal placenta
+ Extrauterine gravidity
+ Gestational trophoblastic disease (GTD)
+ Hydatidiform mole
+ Complete mole
+ Partial mole
+ Invasive mola (mole proliferans, mole destruens)
+ Gestational choriocarcinoma
+ Placental site trophoblastic tumor
+ Placenta and major chromosomal abnormalities
+ Hydropic placenta
+ Pathology of the umbilical cord
+ Abnormal length
+ Short cord
+ Long cord
+ Insertion abnormalities
+ Abnormal coiling
+ Umbilical vessels pathology
+ Umbilical cord accidents which compromise the blood flow
+ Thrombosis of umbilical blood vessels
+ Umbilical cord inflammation
+ Acute funisitis
+ Subacute necrotizing funisitis
+ Miscellaneous rare cord lesions
Pathology of twinning
Marta Ježová

Multiple pregnancy in human is not a physiological event because the anatomy of the human uterus is designed to harbour only one fetus at a time.

  • complications depend on the type of placentation
  • monochorionic twins especially show a high incidence of intrauterine and perinatal complications
  • dizygotic twins:
    • 11 – 12 : 1000 childbirths in our population i.e. every 80 – 90th childbirth
    • incidence is strongly affected by race, heredity, number of previous pregnancies, and maternal age (incidence is higher among multiparas; there is a hereditary trait on the mother's side)
  • monozygotic twins:
    • 3.5 – 4 : 1000 childbirths
    • incidence is not influenced by any of the factors mentioned above
  • with IVF/ET (ovulation induction, transfer of a more than one embryo) the incidence of twins is even 20× higher than in a case of spontanous conception
  • forms of fertilization:
    • dizygotic (biovular): two eggs are fertilized, the fetuses may or may not be of the same sex
    • monozygotic (uniovular): only one egg is fertilized, which later divides into 2 embryos, always of the same sex.
  • forms of placentation:
    • completely separate placentae.
    • dichorionic diamnionic placenta: two fetuses nidate close together and their two separate placentas fuse, so that they macroscopically look like a single placenta. Septum between the fetuses is thick and non-transparent, formed by these layers: amnion —  chorion — chorion — amnion. Blood circulations of the fetuses remain separate.
    • monochorionic diamnionic: single placenta, the twins share one vascular chorion but each fetus is in its own amnionic cavity. The septum between the twins is thin and transparent (made up of two layers of amnion only). Blood circulations are often connected.
    • monochorionic monoamnionic: The twins share both chorion and amnion, there is no septum between them. Blood circulations are heavily interconnected.
  • zygosity and placentation, the rules:
    • dizygotic twins: each has its own placenta, but these can fuse together (dichorionic diamnionic)
    • monozygotic twins: more complicated, type of placentation depends on the timing of the twinning event:
      • 0 – 2nd day: dichorionic diamnionic or even completely separate placentas
      • 2 – 9th day after fertilization: monochorionic diamnionic, this form is most frequent
      • 9 – 13th day: monochorionic monoamnionic
      • A very rare anomaly are so-called Siamese twins (conjoined twins). The twinning event occurs late (13 – 14 day) the zygote fails to split completely. These twins always share one placenta and one umbilical cord and also share various body parts and internal organs (this is not the result of fusion of the twins). For more detailes see the chapter Monsters.

Placenta of biamnial biplacental twins (73280)

Twins and bichorial biamnial placenta (73974)

Clinical signs
  • higher mortality and morbidity of twins compared to singletons
    • pathology during intrauterine developement is due to:
      • umbilical cord accidents
      • twin transfusion syndrome
      • slightly higher incidence of congenital malformations
    • pathology of delivery:
      • preterm labor
      • pathology of the second stage of delivery
      • hypoxia, twin B is in risk
    • postpartum period: complications related to prematurity because most twins are born before 37th w.g.
  • there are also well known risks for the mother:
    • higher incidence of preeclampsia
    • hyperemesis gravidarum
    • high incidence of cesearean section delivery

Fetal death in multiple pregnancy:

Suprisingly many pregnancies begin as multiple, but one fetus usually dies sooner than multiple gravidity is recognized (before 10th w.g):

  • the dead embryo may be completely resorbed
  • the dead embryo remains as a small amorphous disk in the fetal membranes of the surviving twin —  vanishing twin syndrome
  • if one fetus demises in later stages of development, the dessicated body is compressed which is calles fetus compressus (fetus papyraceus)