Placenta
Placental gross/microscopic abnormalities, nonneoplastic
Mesenchymal dysplasia


Topic Completed: 1 October 2011

Minor changes: 18 February 2019

Copyright: 2002-2019, PathologyOutlines.com, Inc.

PubMed Search: Mesenchymal dysplasia placenta

Mandolin S. Ziadie, M.D.
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Cite this page: Ziadie MS. Mesenchymal dysplasia. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/placentapmd.html. Accessed September 30th, 2020.
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
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
Gross images

Contributed by Dr. Govindaswamy Koteeswaran, Mahatma Gandhi Medical College and Research Institute, Puducherry (India)

Various images

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
Microscopic (histologic) images

Contributed by Dr. Govindaswamy Koteeswaran, Mahatma Gandhi Medical College and Research Institute, Puducherry (India)

Various images

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