Table of Contents
Definition / general | Case reports | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) imagesCite this page: Ziadie MS. Mesenchymal dysplasia. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/placentapmd.html. Accessed December 2nd, 2024.
Definition / general
- Rare disorder characterized by an enlarged, abnormal placenta due to overgrowth and vascular abnormalities
- May be associated with fetal overgrowth syndromes, omphalocele or mosaicism
Case reports
- 25 year old woman with enlarged placenta containing numerous grape-like cysts (Case of the Week #193)
- 26 year old woman with full term pregnancy delivered a dead fetus with a clinical diagnosis of partial hydatidiform mole (Case of Placental Mesenchymal Dysplasia)
Gross description
- Bulky placenta with a "bed of yarn" appearance to the maternal surface
- Large, dilated vessels on the chorionic plate that may be thrombosed or have aneurysms
- Resembles a partial mole
Microscopic (histologic) description
- Dilated thick walled chorionic plate vessels with fibromuscular hyperplasia
- Stem villi are enlarged and hypervascular with hydropic stroma and central cisterns that may be lined by lymphatic endothelium (Placenta 2009;30:654) and are filled with gelatinous material
- No trophoblastic hyperplasia is present
- Intermediate villi show chorangiomatosis-like changes with abnormal vascular branching / dilatation
- Terminal villi may be normal or immature