Placental infarct

Placental infarct
Diagnosis in short
Placental infarct. H&E stain.
LM	necrosis of villi (hyaline material replaces the stroma of the villi) with loss of intervillous space, increased numbers of villi with syncytial knots (adjacent to infarct), thickened trophoblastic basement membrane (below cytotrophoblasts), +/-changes seen in decidual vasculopathy
LM DDx	perivillous fibrin deposition
Gross	lesion - red (early), white/grey (late)
Site	placenta
Associated Dx	+/-hypertension
Prognosis	dependent on size and location

Placental infarct is the death of placental tissue due to a compromised blood supply.

It should be noted that a maternal floor infarct is not a true infarct, and is dealt with separately in its own article.

General

• May be seen in conjunction with a retroplacental hematoma.
• Infarcts frequently associated with hypertension.
• May be seen in fetal thrombotic vasculopathy.

Gross

Features:

• Early - red.
• Late - white/grey.

Significant infarcts

• > 3cm --or-- central location --or-- in 1st or 2nd trimester.^{[citation needed]}
  • Small foci are accepted in term placentae - typically at periphery.

Images:

• Placental infarcts (pathweb.uchc.edu).
• Placental infarcts (med.utah.edu).

Microscopic

Features:

1. Necrosis of villi; hyaline material (acellular eosinophilic material) replaces the stroma of the villi.
2. Loss of intervillous space.
   • Villi appear to be crowded.
     • Normal spacing is ~1x smallest villus or larger.
       • In perivillous fibrin deposition - spacing usu. larger than normal.
3. Increased numbers of villi with syncytial knots. ‡
4. Thickened trophoblastic basement membrane (below cytotrophoblasts).
5. +/-Changes seen in decidual vasculopathy:
   • Acute atherosis (vaguely like atherosclerosis).
     • Fibrinoid necrosis.
     • Vessel wall lipid deposition.

Note:

• ‡ The normal number is dependent on the gestational age:

Gestational age	Villi with knots (average)	Villi with knots (range)
40 weeks	29 %	27-36 %
39 weeks	29 %	23-34%
38 weeks	27 %	23-33 %
37 weeks	28 %	24-33 %
36 weeks	23 %	20-26 %
35 weeks	22 %	15-32 %
34 weeks	18 %	12-22 %
32 weeks	13 %	10-16 %
30 weeks	13 %	10-17 %
26 weeks	11 %	10-13 %
22 weeks	7 %	5-9 %

Images

• 

  Placental infarct - low mag. (WC)

• 

  Placental infarct - intermed. mag. (WC)

www:

• Recent infarct (pathweb.uchc.edu).
• Placental infarct (umpmc.edu).
• Placental infarct - necrotic villi (mda-sy.com).

Sign out

PLACENTA, UMBILICAL CORD AND FETAL MEMBRANES, BIRTH:
- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.
- FETAL MEMBRANES WITHIN NORMAL LIMITS.
- PLACENTAL DISC WITH THIRD TRIMESTER VILLI AND TWO PLACENTAL INFARCTS (0.6 CM AND 
  0.4 CM IN MAXIMAL DIMENSION).

Increased syncytial knots

PLACENTA, UMBILICAL CORD AND FETAL MEMBRANES, BIRTH:
- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.
- FETAL MEMBRANES WITHIN NORMAL LIMITS.
- PLACENTAL DISC WITH THIRD TRIMESTER VILLI WITH FOCALLY INCREASED SYNCYTIAL KNOTS,
  AND MILD PERIVILLOUS FIBRIN DEPOSITION, OTHERWISE WITHIN NORMAL LIMITS.

See also

• Placenta.
• Maternal floor infarct.
• Infarct.
• Perivillous fibrin deposition.