Table of ContentsDefinition / general | Essential features | Risk factors | Clinical features | Radiology description | Case reports | Treatment | Gross description | Microscopic (histologic) description | Positive stains | Negative stains | Electron microscopy description | Differential diagnosis | Board review style question #1 | Board review style answer #1
Cite this page: Garg S. Chorangioma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/placentachorangioma.html. Accessed January 22nd, 2021.
Definition / general
- Most common tumor of the placenta (incidence 1%) (Rare Tumors 2010;2:e67)
- Considered hamartoma-like or hyperplastic capillary lesion rather than a true neoplasm
- If size > 4 - 5 cm, associated with significant effects on the fetal hemodynamic and circulatory processes leading to clinical complications (J Clin Diagn Res 2016;10:ED03)
- These tumors have no malignant potential
- Arise from major stem villi under the chorionic plate or at the placental margin
- Angiomatous (capillary) are the most frequent histologic type
- Chorangiomas must be differentiated from other villous capillary lesions, namely chorangiomatosis and chorangiosis
- Atypical chorangioma: rare, characterized by increased cellularity and mitotic activity, necrosis and solid areas, may resemble sarcoma but has benign behavior (Int J Surg Pathol 2015;23:364)
- More common in high altitudes (hypoxia related), increased maternal age, diabetes, hypertension, multiple pregnancy
- Most are small in size and found incidentally; some tumors regress spontaneously
- Large (> 4 - 5 cm) and multiple chorangiomas are associated with maternal and fetal complications (30 - 50%) (Case Rep Obstet Gynecol 2012;2012:913878)
- Complications include (Indian Pediatr 1996;33:520):
- Preterm labor
- Fetal congestive cardiac failure (due to arteriovenous shunt)
- Fetal hemolytic anemia / thrombocytopenia
- Obstetric ultrasound images may show hypoechoic circumscribed intraplacental mass containing small anechoic spaces
- 26 year old woman presented at 36 weeks gestation with polyhydramnios and abdominal pain (J Clin Diagn Res 2016;10:ED03)
- 27 year old pregnant woman with overdistended abdomen and ultrasound findings of a well defined 12 cm echogenic mass on the fetal surface of placenta (Case Rep Obstet Gynecol 2012;2012:913878)
- In situations where maternal and fetal complications exist, possible interventions include (Fetal Pediatr Pathol 2010;29:199):
- Serial fetal transfusions (Ginekol Pol 2011;82:304)
- Fetoscopic laser coagulation of vessels
- Chemosclerosis with absolute alcohol
- Endoscopic surgical devascularization
- Interventions however, all carry dismal prognosis
- Solitary or multiple nodules mostly located on the chorionic plate and or placental margin
- Mostly fleshy, congested, red / tan cut surface resembling a blood clot, when perfused
- May appear as a firm white lesion when infarcted
Microscopic (histologic) description
- Well circumscribed mass arising from stem villi and resembling capillary hemangioma; distinct demarcation from surrounding normal parenchyma
- Proliferation of capillary sized vessels causing expansion of contiguous affected villi
- Composed of a mixture of endothelial cells, pericytes and myofibroblastic stromal cells
- There may be associated nonspecific surface trophoblastic proliferation (up to 40% cases), which is benign
- Occasionally associated with degenerative changes like hyalinization, necrosis and calcification
Electron microscopy description
- Normal endothelial cells and various vascular structures
Board review style question #1
Which of the following is not associated with atypical chorangioma?
- Immunohistochemical staining for factor VIII antigen.
- Increased cellularity and high mitotic activity.
- Invasion, metastasis and biological aggressiveness.
- Large tumor size.
- Tumor necrosis.
Board review style answer #1
C. Atypical chorangioma may be associated with increased cellularity, high mitotic activity, tumor necrosis, positive staining with factor VIII antigen and may have large tumor size. It however, lacks metastasis, invasion or biological aggressiveness.