Placenta

Gestational trophoblastic disease

Nonneoplastic lesions

Exaggerated placental site



Last author update: 20 December 2021
Last staff update: 28 June 2022

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PubMed Search: Exaggerated placental site

Absia Jabbar, M.D.
Raavi Gupta, M.D.
Page views in 2021: 10,571
Page views in 2022 to date: 12,648
Cite this page: Jabbar A, Lanjewar S, Gupta R. Exaggerated placental site. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/placentaexagg.html. Accessed December 10th, 2022.
Definition / general
  • Exuberant infiltration of the endometrium and myometrium by implantation site intermediate trophoblast
Essential features
  • Exaggeration of normal physiologic process, with infiltration of the endometrium and superficial third of myometrium by implantation site intermediate trophoblast
  • Can be associated with normal pregnancy or abortions, molar pregnancy and sometimes presents as postpartum bleeding
  • Ki67 labeling index is near 0%
  • Ki67 labeling index can be 0 - 5 % in exaggerated placental site (EPS) of molar pregnancies (Hum Pathol 1998;29:27)
ICD coding
  • ICD-10: O43.899 - other placental disorders, unspecified trimester
Epidemiology
Sites
  • Uterus
Pathophysiology
  • Exaggeration of normal physiologic process
  • Intermediate trophoblasts (IT) invade through endometrium into the superficial third of myometrium (Int J Gynecol Pathol 2001;20:31)
  • Normal structure of endometrial glands, myometrium and vessels is usually maintained
  • Ki67 indices of near zero indicate increased number of intermediate trophoblasts in EPS is not a result of de novo proliferation of IT in the implantation site (Hum Pathol 1998;29:27)
  • Increased Ki67 in molar pregnancy may be a spillover effect IT in the trophoblastic columns of hydatiform moles (Hum Pathol 1998;29:27)
  • Although histologically the same, increased Ki67 labelling index in complete molar implantation site represents related but different lesions (Hum Pathol 1998;29:27)
Clinical features
Diagnosis
  • Histologic examination
Radiology description
Prognostic factors
  • Excellent prognosis following curettage
Case reports
Treatment
Microscopic (histologic) description
  • Extensive infiltration of endometrium and myometrium by implantation site intermediate trophoblasts which are often multinucleate (Int J Gynecol Pathol 2001;20:31)
  • Endometrial glands and spiral arterioles can show invasion by trophoblasts
  • Smooth muscle cells of myometrium are separated by cords, nests and individual trophoblastic cells
  • Despite diffuse infiltration, there is not necrosis or mitoses
  • Trophoblastic cells share similar morphologic features of normal implantation site intermediate trophoblasts; these cells contain abundant eosinophilic cytoplasm with hyperchromatic and irregular nuclei (Int J Gynecol Pathol 2001;20:31)
  • Chorionic villi are morphologically unremarkable
Microscopic (histologic) images

Contributed by Raavi Gupta, M.D., Absia Jabbar, M.D. and Sonali Lanjewar, M.D., M.B.B.S.
Intermediate trophoblasts invading myometrium Intermediate trophoblasts invading myometrium Intermediate trophoblasts invading myometrium Intermediate trophoblasts invading myometrium Intermediate trophoblasts invading myometrium Intermediate trophoblasts invading myometrium

Intermediate trophoblasts invading myometrium

Virtual slides

Images hosted on other servers:
Exaggertated placental site

Exaggertated placental site

Positive stains
Negative stains
Sample pathology report
  • Uterus, endometrium, dilatation and curettage:
    • Exaggerated placental site
Differential diagnosis
Board review style question #1

Exaggerated placental site (shown in the image above) is characterized by which of the following features?

  1. Absence of villi
  2. Presence of necrosis and mitoses
  3. Proliferation of chorionic type intermediate trophoblasts with invasion of myometrium
  4. Proliferation of implantation type intermediate trophoblasts with invasion of myometrium
Board review style answer #1
D. Proliferation of implantation type intermediate trophoblasts with invasion of myometrium

Comment Here

Reference: Exaggerated placental site
Board review style question #2
Ki67 labeling index in exaggerated placental site is

  1. Near 0%
  2. Near 5%
  3. Near 15%
  4. Near 100%
Board review style answer #2
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