Pathology: Placenta Flashcards Preview

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Flashcards in Pathology: Placenta Deck (34)
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Structure of normal placenta (and changes from first to third trimester)

First-trimester: chorionic villi composed of delicate mesh of central stroma surrounded by two discrete layers of epithelium—
• the outer layer consisting of syncytiotrophoblast and
• the inner layer consisting of cytotrophoblast.

Third-trimester: chorionic villi composed of stroma with dense network of dilated capillaries surrounded by markedly thinned-out syncytiotrophoblast and cytotrophoblast


Causes of fetal growth restriction

May result from fetal, maternal, or placental abnormalities:
- Fetal: symmetric growth restriction may result from chromosomal disorders, congenital anomalies, and congenital infections (TORCH = Toxoplasmosis, Others such as syphilis, Rubella, CMV, Herpesvirus)
- Maternal: conditions that result in decreased placental blood flow, common causes include vascular dz (i.e., coagulopathies, pre-eclampsia) and chronic HTN
- Placental: asymmetric, spares the brain; uteroplacental insufficiency may result from umbilical-placental vascular anomalies, placental abruption, previa, thrombosis/infarction, infection, or mult. gestations


Causes of spontaneous abortion/miscarriage

(defined as pregnancy loss before 20 weeks gestation)
- 50% have fetal chromosome anomalies
- maternal endocrine factors: luteal-phase defect uncontrolled DM, others
- physical defects of the uterus can prevent/disrupt implantation: submucosal leiomyoma, uterine polyps, uterine malformations
- systemic disorders affecting the maternal vasculature: antiphospholipid Ab syndrome, coagulopathies, HTN


Major common causes of pregnancy loss in each trimester

1st - chromosomal anomalies
2nd - ascending infection; fetal/maternal anatomic defects
3rd - usually placental insufficiency


Histologic findings of Listeria infection

necrotizing intervillositis


Histologic findings of CMV infection

chronic villitis
Owl eye nuclear inclusions as well as cytoplasmic inclusions (herpes only has nuclear - that's a distinction)
Also, the cell is HUGE (hence, -megalovirus)


Histologic findings of Parvovirus B19 infection

- viral inclusions in erythroid precursors
- erythroblasts in the lumen of capillaries of placental villi show eosinophilic nuclear inclusions
(the illness is called erythema infectiosum, or fifth disease; presents with body rash and a "slapped cheek" appearance)


Twin-twin transfusion syndrome

a complication of monochorionic twin placentas where the blood is shunted to one twin at the expense of the other; one is underperfused and the other is fluid overloaded; may result in the death of one or both twins


Ectopic pregnancy

a fertilized ovum implanted anywhere it's not supposed to be; most common site is extrauterine fallopian tubes (~90% of cases)


Placenta previa

a very low lying placenta or a placenta which cover the os; severe hemorrhage can result with cervical dilation and passage of the baby through the birth canal


Placenta accreta

a lack of formation of a normal decidual plate (supposed to sit between the placenta and myometrium), therefore the chorionic villi interdigitate directly with the uterine myometrium. The placenta cannot separate normally following delivery; severe hemorrhage results


Abruptio placenta

premature separation of the placenta prior to delivery, with formation of a retroplacental blood clot; a larger abruption more greatly compromises blood supply to the fetus


Classification of placental invasion into myometrium

- accreta = superficial invasion into myometrium
- increta = deep invasion into myometrium
- percreta = invades through the myometrium


Amnion nodosum

- Multiple yellow-tan superficial amniotic lesions, 0.2 to 0.4 cm and usually near insertion of umbilical cord
- micro: nodules of protuberant eosinophilic fibrinous material with entrapped squamous cells; associated with stratified squamous metaplasia
- seen in placentas affected by oligohydramnios, which may be associated with fetal renal agenesis and pulmonary hypoplasia
- may be due to desquamated skin or membrane injury


Potter's sequence - features and cause

- features: clubbed feet, pulmonary hypoplasia, and cranial anomalies, like flattened facies and low set ears
- due to oligohydramnios (not enough amniotic fluid)



- disorder of pregnancy characterized by HTN and proteinuria
- causes villous ischemia of placenta, fibrinoid necrosis of **maternal** vessel walls in the decidua
- most placentas are smaller than expected, infarcts and retroplacental hematomas are common


Hydatidiform Mole

- a non-viable fertilized egg that implants into the uterus
- associated with **inc. risk of persistent trophoblastic disease (invasive mole) or choriocarcinoma**
- check p57 IHC


Complete mole

an egg that has no DNA that gets fertilized; has no embryo, no normal placenta, *marked villous enlargement* , edema, and circumferential trophoblastic proliferation
**all paternal** No fetal parts
**Snowstorm appearance on ultrasound**
Labs: HIGH hCG


Partial mole

an egg with DNA that gets fertilized by 2 sperm (so often ends up as **triploid**); *some villi will appear normal, others swollen*, avascular, and grape-like; minimal trophoblastic proliferation
- can have fetal parts
Labs: elevated hCG, not as high as complete mole



- malignant neoplasm of trophoblastic cells derived from a previously normal or abnormal pregnancy
- histo will see proliferating syncytiotrophoblasts and cytotrophoblasts; mitoses are abundant and sometimes abnormal
- soft, fleshy, yellow-white tumor; usually with large pale areas of necrosis and **extensive hemorrhage**
- rapidly invasive and **metastasizes widely**, gets into the underlying myometrium, frequently penetrates blood vessels
- very high hCG levels; *responds well to chemo*


Placental site nodule or plaque

a rare proliferation of intermediate trophoblast that is microscopic; of no major clinical consequence


Placental Site Trophoblastic Tumor

a rare localized proliferation of intermediate trophoblast that can produce a grossly visible nodule; most are benign but there are rare malignant cases


Necrotizing enterocolitis (NEC)

a complication of premature birth consisting of infarction and transmural necrosis of the bowel, *wall becomes perilously thin with impending perforation*
-Grossly, submucosal gas bubbles may be seen (pneumonitis intestinalis)


Neonatal respiratory distress syndrome, also known as hyaline membrane disease

- results from reduced surfactant synthesis/storage/release and increased alveolar surface tension
- alternating atelectasis and dilation of the alveoli with eosinophilic thick hyaline
- leads to hypoxemia and CO2 retention and acidosis, pulm. VC and hypoperfusion means endothelial damage and plasma leak into alveoli; fibrin/debris form hyaline membrane


Fetal hydrops

- accumulation of edema fluid in the fetus during intrauterine growth
- causes include CV, chromosomal, fetal anemia, Parvo B19, homozygous alpha-thalassemia, twin-twin, etc.
- Immune hydrops (MCC) = reactions of the Rh antigens and ABO blood groups that occurs in second and subsequent pregnancies; Abs to Rh+ RBCs cause their removal, get anemia, cardiac decompensation, and hydrops, as well as Hgb degradation, bilirubin, jaundice
- Strong association with Turner's Syndrome (45X)


Cystic hygroma

- a condition in which fluid accumulates in the soft tissues of the neck; looks like a fan around the neck
- characteristically seen, but not limited to, in chromosomal anomalies like 45X



- the sudden death of an infant from an unexplained cause (remains unexplained after investigation and autopsy)


Klinefelter syndrome

- lost Sertoli cells, lost inhibin, and inc. FSH
- FSH --> aromatase, inc. estrogen
- female SSCs at puberty


Androgen Insensitivity Syndrome (AIS)

- XY phenotypic female
- no testosterone receptor activity, no conversion to DHT, no male structural development
- AMH is present so there's no female structures, but the distal 2/3 (vagina) and breasts form due to estrogen


Premature ovarian failure

- loss of ovarian function, so dec. estrogen and inhibin feedback results in inc. FSH/LH
- presents as female, >40yo, with amenorrhea; progesterone withdrawal test is negative for bleeding


Polycystic ovarian syndrome (PCOS)

- increased LH increases testosterone and conversion to estrogen
- high LH inhibits FSH; no follicle development and follicle becomes a cyst
- female presents with hirsutism, amenorrhea; progesterone test is positive for bleeding


Turner syndrome

- 45X– monosomy
- presents as lymphedema at birth, primary amenorrhea
- patient is short, shield chest, wide nipples, webbed neck, low hair line, coarctation of aorta, streak ovaries, little estrogen, elevated FSH/LH


Kallman syndrome

- defective production of GnRH
- associated with anosmia (inability to smell)


Inflammation of umbilical vessels (vasculitis) and cord substance (funisitis) occurs in response to infection, and constitutes the fetal or maternal inflammatory response?