Testis and epididymis
Germ cell tumors
Polyembryoma

Author: Andres Matoso, M.D. (see Authors page)

Revised: 14 September 2017, last major update September 2017

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Testis polyembryoma

Cite this page: Matoso, A. Polyembryoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/testispolyembryoma.html. Accessed October 18th, 2017.
Definition / general
  • Mixed germ cell tumor with predominant embryoid bodies (central core of embryonal carcinoma cells, amnion-like cavity and yolk sac tumor component)
  • Elements other than the embryoid bodies, however, should constitute less than 10% of the tumor for the "polyembryoma" designation to be used (Mod Pathol 2005;18:S61)
  • Resembles embryonic yolk sac
  • Behaves like other mixed germ cell tumors
Essential features
  • Central core of embryonal carcinoma cells, amnion-like cavity and yolk sac tumor component that accounts for approximately 90% of tumor
Epidemiology
Clinical features
  • Same as germ cell tumors
  • Elevation of serum AFP and beta HCG
Prognostic factors
  • Same as mixed germ cell tumors
Treatment
  • Same as mixed germ cell tumor with teratoma
Microscopic (histologic) description
  • At low power, the stroma can give the tumor a lobular architecture
  • Embryoid bodies are composed of a hyperchromatic disc of embryonal carcinoma
  • Surrounding the disc of embryonal carcinoma is edematous stroma forming a cavity lined by yolk sac epithelium
Microscopic (histologic) images

Images hosted on other servers:

Various images

Positive stains
Negative stains
Board review question #1
What is the difference between a mixed germ cell tumor with embryoid bodies and a polyembryoma?

  1. Mixed germ cell tumors have components other than embryonal carcinoma and yolk sac tumor, while polyembryomas have only embryonal carcinoma and yolk sac tumor.
  2. Polyembryoma is not a germ cell tumor.
  3. Polyembryomas have many different types of embryoid bodies.
  4. Proportion of embryoid bodies in polyembryomas is 90% or higher of the entire tumor.
Board review answer #1
D. Proportion of embrioid bodies in polyembryomas is 90% or higher of the entire tumor.