Placenta
Nontrophoblastic neoplasms
Hepatocellular adenoma-like lesion of placenta

Author: Shipra Garg, M.D. (see Authors page)

Revised: 20 November 2017, last major update November 2017

Copyright: (c) 2003-2017, PathologyOutlines.com, Inc.

PubMed Search: Hepatocellular adenoma placenta
Cite this page: Garg, S. Hepatocellular adenoma-like lesion of placenta. PathologyOutlines.com website. http://pathologyoutlines.com/topic/placentahepatocellularadenoma.html. Accessed November 21st, 2017.
Definition / general
  • Extremely rare benign nontrophoblastic lesion (about 9 cases have been reported so far)
  • May represent a liver heterotopia or specialized monodermal teratoma (Am J Surg Pathol 1998;22:355)
Essential features
Sites
  • Usually presents as a subchorionic intervillous mass or in the villous parenchyma of the placenta
Pathophysiology
  • Exact pathophysiology of ectopic liver in the placenta is unknown
  • Hypothesized that aberrant migration or displacement of cells from the developing hepatic buds leads to ectopic liver formation
  • Groups of liver cells become entrapped in the foregut as the diaphragm closes (Pediatr Dev Pathol 2017 Jan 1 [Epub ahead of print])
  • It may represent a specialized monodermal teratoma in the placenta
Clinical features
  • Usually an incidental finding
Case reports
Gross description
  • Small (0.3 - 1.0 cm), well circumscribed tan to dark red nodules in the placental parenchyma
  • May be encapsulated
  • Without necrosis or hemorrhagic foci
  • Sometimes may not be grossly visible
Microscopic (histologic) description
  • Well circumscribed mass composed of semi distinct lobules of cords and nests of polygonal epithelial cells with pink and focally clear cytoplasm resembling fetal hepatocytes (Int J Gynecol Pathol 1998;17:241)
  • No portal tracts, bile ducts or central veins are identified
  • Extramedullary hematopoiesis is a constant feature
  • Lesional cells contain glycogen
  • No nuclear atypia, cellular pleomorphism or mitotic activity
  • No globular cytoplasmic inclusions, intracytoplasmic hyaline or bile pigment
Positive stains
Negative stains
Electron microscopy description
  • Tumor cells contain numerous glycogen granules, diffusely scattered endoplasmic reticulum and multiple mitochondria
  • Cell membranes of adjacent cells are joined by desmosomes
  • Structures resembling bile canaliculi are found (Am J Surg Pathol 1986;10:436)
Differential diagnosis
  • Metastatic or primary hepatocellular carcinoma (reticulin stain shows increased plate thickness)
  • Heterotopic adrenocortical nodule, chorangioma and placental metastasis of maternal and fetal malignancies
Board review question #1
    Which of the following is true?

  1. Hepatocellular adenoma of the placenta is a benign and extremely rare lesion.
  2. Histologically, it presents as a well circumscribed mass composed of nests and cords of epithelial cells resembling fetal hepatocytes.
  3. It may actually represent liver heterotopia or a specialized monodermal teratoma in placenta.
  4. All of the above.
Board review answer #1
D. All of the above.