Placenta

Nonneoplastic placental conditions and abnormalities

Noninfectious

Chorangiosis


Editorial Board Member: Ricardo R. Lastra, M.D.
Deputy Editor-in-Chief: Jennifer A. Bennett, M.D.
Anh Huynh, M.D.
Drucilla J. Roberts, M.D.

Topic Completed: 2 September 2021

Minor changes: 2 September 2021

Copyright: 2003-2021, PathologyOutlines.com, Inc.

PubMed Search: Chorangiosis placenta

Anh Huynh, M.D.
Drucilla J. Roberts, M.D.
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Cite this page: Huynh A, Roberts DJ. Chorangiosis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/placentachorangiosis.html. Accessed September 20th, 2021.
Definition / general
Essential features
  • Terminal villous vascular hyperplasia resulting from longstanding low grade hypoxia in the placental tissue or fetal side hypoperfusion
ICD coding
  • ICD-10: O43.89 - other placental disorders
Epidemiology
Sites
  • Terminal chorionic villi of the placenta
Pathophysiology
  • Growth factor promotion of angiogenesis in response to long standing placental hypoperfusion or chronic low grade tissue hypoxia
  • Chronic hypoperfusion and tissue hypoxemia may lead to an excessive villous neoangiogenesis and to a high proliferative activity of connective tissue, probably mediated by growth factors (VEGF, bFGF and PDGF) (Gynecol Obstet Invest 2012;73:141)
Etiology
  • Higher incidence in maternal pathological conditions associated with hypoxemia
  • Incidence is higher:
  • Also associated with placental pathology, such as single umbilical artery, placental abruption, amnion nodosum, villitis and umbilical cord anomalies (e.g. long umbilical cord)
Clinical features
Diagnosis
  • Altshuler criteria: > 10 capillaries in at least 10 terminal villi in ≥ 10 noninfarcted areas in at least 3 low power fields of the placenta (Arch Pathol Lab Med 1984;108:71)
  • Normal villi rarely have > 5 capillaries / villous
Prognostic factors
Case reports
Gross description
  • No distinct gross abnormalities
  • Placenta may be heavy and boggy
  • Other placental findings may include: single umbilical artery and other umbilical cord anomalies, retroplacental hematoma (abruptio placentae) (Gynecol Obstet Invest 2012;73:141)
Microscopic (histologic) description
  • > 10 capillaries in > 10 terminal villi in at least 10 different noninfarcted areas in 3 low power fields of the placenta = diffuse chorangiosis
  • Focal chorangiosis with similar morbidity associations as diffuse (Pediatr Dev Pathol 2019;22:406)
  • Capillaries have distinct basement membranes but are not surrounded by a continuous layer of pericytes or associated with stromal fibrosis
  • May be associated with delayed villous maturation, chorangioma(s), villitis of unknown etiology, fetal vascular malperfusion
  • Must distinguish from villous vascular congestion (vessels appear prominent but are normal in number), chorangiomatosis and chorangioma(s)
Microscopic (histologic) images

Contributed by Drucilla J. Roberts, M.D.

Term placenta showing chorangiosis

Positive stains
Sample pathology report
  • Placenta:
    • Heavy, slightly immature placenta (650 g fresh, trimmed; > 90th percentile for 39 weeks gestational age)
    • Long umbilical cord (85 cm, expect 50 - 70 cm at term)
    • Chorangiosis, diffuse (see comment)
    • Comment: Chorangiosis, when diffuse, is a rare finding associated with in utero hypoxia.
Differential diagnosis
  • Chorangioma:
    • Nodular lesion composed entirely of capillary vascular channels with surrounding trophoblasts
    • Analogous to hemangiomas occurring elsewhere
  • Chorangiomatosis:
    • Heterogeneous and less well defined lesion with intermediate features between chorangioma and chorangiosis
    • Hyperplastic capillaries surround larger vessels in central cores of stem and intermediate villi
    • Increased number of perivascular bundles of reticulin fibers and pericytes
    • Smooth muscle actin positive in pericytes
  • Congestion:
    • Prominent capillaries in the villi but there is no numerical increase in the number of capillaries
Board review style question #1

This placenta from a primigravida living in Nepal shows what feature?

  1. Chorangioma
  2. Chorangiomatosis
  3. Chorangiosis
  4. Normal placenta villi
  5. Villous edema
Board review style answer #1
C. Chorangiosis

Comment Here

Reference: Chorangiosis
Board review style question #2

Chorangiosis (see figure) is associated with which of these clinical histories?

  1. CMV placentitis
  2. High altitude pregnancies
  3. Intrauterine fetal demise
  4. Maternal depression
  5. Small for gestational age fetus
Board review style answer #2
B. High altitude pregnancies

Comment Here

Reference: Chorangiosis
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