Download Pediatric Pathology

Pediatric Pathology
“Children are not merely little adults, and
their diseases are not merely variants of
adult diseases”
Cause of Death Related with Age
UNDER 1 YEAR
• Congenital malformations, deformations, and
chromosomal anomalies
• Disorders related to short gestation and low birth weight
• Sudden infant death syndrome (SIDS)
• Newborn affected by maternal complications of
pregnancy
• Newborn affected by complications of placenta, cord, and
membranes
• Respiratory distress of newborn
• Accidents (unintentional injuries)
• Bacterial sepsis of newborn
• Intrauterine hypoxia and birth asphyxia
• Diseases of the circulatory system
1–4 YEARS
• Accidents and adverse effects
• Congenital malformations, deformations, and
chromosomal abnormalities
• Malignant neoplasms
• Homicide and legal intervention
• Diseases of the heart (Excludes congenital heart disease)
• Influenza and pneumonia
5–14 YEARS
• Accidents and adverse effects
• Malignant neoplasms
• Homicide and legal intervention
• Congenital malformations, deformations, and
chromosomal abnormalities
• Suicide
• Diseases of the heart
15–24 YEARS
• Accidents and adverse effects
• Homicide
• Suicide
• Malignant neoplasms
• Diseases of the heart
Congenital Anomalies
• morphologic defects that are present at birth
• the exact cause remains unknown in at least
half to three quarters of the cases
• common known causes of congenital
anomalies:
– Genetic
– Environmental
– Multifactorial
Genetic
• Anomalies that are known to be genetic in
origin can be divided into two groups:
– Those associated with chromosomal aberrations
– Those arising from single-gene mutations
(“mendelian disorders”)
trisomy 21 (Down syndrome) is the only one
that approaches a birth frequency of greater
than 10 in 10,000 total births
Fetal Hydrops
• accumulation of edema fluid in the fetus
during intrauterine growth
• Two Causes:
– Immune
– Nonimmune
Immune Hydrops
• Antibody induced hemolytic disease in the
newborn caused by blood group
incompatibility between mother and fetus.
• Rh and ABO blood group antigens, most
common antigens.
Nonimmune Hydrops
• Cardiovascular Defetcs.
a. structural
b. functional
• Chromosomal anomalies.
a. 45,X karyotype (Turner syndrome)
b. Trisomies 21 and 18
- the basis of this is the presence of underlying
structural cardiac anomalies
• Fetal Anemia due to causes other than Rh and
ABO incompatibility.
Fetal Anemia
• Homozygous alpha thalassemia – most
common cause of HF in Southeast Asia
• Transplacental infection e.g. Parvovirus B19
– Virus gains entry into erythroid precursors
(normoblasts), where it replicates.
– Leads to erythrocyte maturation arrest and
aplastic anemia
– Parvoviral intranuclear inclusions can be seen
within circulating and marrow erythroid
precursors
Pathogenesis of Hydrops
Severe anemia
Hepatic extramedullary hematopoeisis
Decreased prdtn of plasma proteins
Decreased oncotic pressure
Pathogenesis of Hydrops
Congestive heart failure
Increased central venous pressure
Increased capillary hydrostatic pressure
Pathogenesis of Hydrops
Severe tissue hypoxia
Endothelial cell damage
Capillary leak of fluid & protein
BENIGN TUMORS AND TUMORLIKE LESIONS
• Hemangioma
– are the most common tumors of infancy
– Types:
• Cavernous
• Capillary
• Teratomas
• Tumor with at least 2 out of 3 germ layers
– benign, well-differentiated cystic lesions (mature
teratomas)
– indeterminate potential
– unequivocally malignant teratomas
MALIGNANT TUMORS
• incidence in children younger than age 10
years include
• (1) leukemia (principally acute lymphoblastic
leukemia)
• (2) neuroblastoma
• (3) Wilms tumor
• (4) hepatoblastoma
• (5) retinoblastoma
• (6) rhabdomyosarcoma
• (7) teratoma
• (8) Ewing sarcoma
posterior fossa neoplasms—principally
• (9) juvenile astrocytoma
• (10) medulloblastoma
• (11) ependymoma
Neuroblastoma
• the most common extracranial solid tumor of
childhood
• most frequently diagnosed tumor of infancy
• one case in 7000 live births
• median age at diagnosis is 18 months
• 40% of cases are diagnosed in infancy
• Most cases occur sporadically
• most (60% to 80%) children present with stage
3 or 4 tumors (unresectable)
Wilms Tumor
• approximately 1 in every 10,000 children in
the United States
• most common primary renal tumor of
childhood
• fourth most common pediatric malignancy in
the United States
• 95% of tumors occur before the age of 10
years
• Involves mutation of the WT1 gene