Table of ContentsDefinition / general | Essential features | Pathophysiology | Etiology | Clinical features | Case reports | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Differential diagnosis | Additional references | Board review style question #1 | Board review style answer #1
Cite this page: Garg S. Chorangiomatosis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/placentachorangiomatosis.html. Accessed May 29th, 2023.
Definition / general
- Nonexpansile vascular proliferation similar to chorangioma but occurring in otherwise normal stem villi
- Associated with preeclampia, multiple gestation, premature delivery at 26 to 32 weeks (Hum Pathol 2000;31:945)
- Divided in localized (focal), segmental and multifocal / diffuse types
- Diffuse multifocal subtype is asssociated with extreme prematurity (< 32 weeks), congenital malformations, intrauterine growth restriction, delayed villous maturation, avascular villi and placentomegaly (Pediatr Dev Pathol 2011;14:38)
- Villous capillary lesion occurring due to reactive hyperplasia to hypoxia (similar to the other villous capillary lesions of placenta, J Pregnancy 2014;2014:193925)
- Overall prevalence is 0.55% (less common than chorangiosis)
- Heterogeneous and less well defined lesion with features intermediate between chorangioma and chorangiosis
- Capillary hyperplasia occurs as a reaction to tissue hypoxia that stimulates neoangiogenesis by activating growth factors such as VEGF and PDGF.
- Chorangioma and localized chorangiomatosis are etiologically similar hyperplastic lesions arising in subtrophoblastic reticular connective tissue of stem villi
- Chorangioma and chorangiomatosis often coexist
- Associated with maternal preeclampsia, multiple gestation and prematurity
- No definite association with maternal diabetes mellitus (unlike chorangiosis)
- 29 year old woman with luteininized cystic ovarian hyperplasia associated with placentomeglay due to chorangiomatosis (Fetal Pediatr Pathol 2005;24:31)
Microscopic (histologic) description
- Proliferation of small capillaries surrounded by a circumferential layer of pericytes and loose reticulin fibers merging imperceptivity into surrounding villous stroma
- Occurs within the stem villi (contain a dense vimentin positive collagenized core) and does not form a discrete mass
- Focal subtype involves < 5 contiguous villi
- Segmental subtype involves > 5 contiguous villi
- Diffuse / multifocal subtype involves several noncontiguous areas of the placenta
- Occasional cases of diffuse multifocal chorangiomatosis can show peripheral areas of smaller capillaries more typical of chorangiosis
- Endothelial cells of capillaries are highlighted by CD31 and CD34
- Pericytes are highlighted by muscle specific actin
- Reticulin fibers are highlighted by reticulin
- Chorangioma: well circumscribed nodular lesion showing capillary hyperplasia surrounded by trophoblastic cells
- Chorangiosis: individual capillaries are surrounded by distinct basement membranes and there is no circumferential lining of pericytes or loose reticulin bundles
Board review style question #1
Which of the following statements is true?
- Chorangiomatosis arises in the terminal villi of the placenta.
- Chorangiosis is 10 times more prevalent than chorangioma or chorangiomatosis.
- Chorangiomatosis lesion is always negative for muscle specific actin stain.
- All of the above.
Board review style answer #1
B. Chorangiosis is 10 times more prevalent than chorangioma or chorangiomatosis.