Testis and epididymis
Germ cell tumors

Author: Turki Al-Hussain, M.D. (see Authors page)

Revised: 3 July 2017, last major update January 2013

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

PubMed Search: Choriocarcinoma [title] testis

Cite this page: Choriocarcinoma. PathologyOutlines.com website. http://pathologyoutlines.com/topic/testischorio.html. Accessed November 17th, 2017.
Definition / general
  • 0.3% to 1% of germ cell tumors are pure choriocarcinoma but mixed tumors are more common (8%)
  • May present initially with metastases (liver, lung, mediastinum, retroperitoneum) with normal testis or small tumor but with increased serum hCG
  • Identical tumors arise in placenta, ovary, mediastinum or abdomen (from sequestered cell rests)
  • Usually fatal if pure
  • Hematogenous spread early to lungs, liver and brain
Case reports
Gross description
  • Hemorrhagic and necrotic mass, small, may be replaced by fibrous scar with hemosiderin because it outgrows blood supply; resembles disintegrating clot
Microscopic (histologic) description
  • Hemorrhage and necrosis common
  • Cytotrophoblast (polygonal / round cells with distinct cell borders, clear cytoplasm and single bland nucleus) and syncytiotrophoblast (large multinuclear cell with eosinophilic and vacuolated cytoplasm) are closely intermingled in biphasic plexiform pattern as in chorionic villi; only significant if major component of tumor; no effect on prognosis if part of mixed tumor
  • Intratubular germ cell neoplasia in adjacent testis is common
Microscopic (histologic) images

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Cytotrophoblasts and syncytio-trophoblasts

Cytotrophoblastic cells

Syncytio-trophoblastic cells

Abundant syncytio-trophoblasts



Positive stains
Negative stains
Differential diagnosis
  • Hemorrhagic testicular necrosis: trauma, torsion, clotting abnormalities
  • Syncytiotrophoblasts also present in seminoma