Testis and epididymis
Germ cell tumors

Topic Completed: 1 January 2013

Revised: 3 October 2019

Copyright: 2002-2018, PathologyOutlines.com, Inc.

PubMed Search: Seminoma testis [title]

Turki Al-Hussain, M.D.
Page views in 2018: 33,463
Page views in 2019 to date: 39,485
Cite this page: Al-Hussain T. Seminoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/testisseminomas.html. Accessed December 7th, 2019.
Definition / general
  • Also called classic seminoma
  • 30 - 50% of testicular germ cell tumors
  • Mean age 40 years versus 25 years for nonseminomatous germ cell tumors (NSGCT); rare in infants
  • In ovary, called dysgerminoma
  • Also present in mediastinum, pineal gland (germinoma), retroperitoneum
Clinical features
  • 70% have stage 1 disease
  • May metastasize to lymph nodes or bone; late hematogenous spread may occur
  • Presence of elevated serum hCG does not change classification and has no clinical significance; however elevated AFP indicates a nonseminomatous germ cell component (or liver disease), even if not seen histologically
  • 40% have increased serum PLAP (placental alkaline phosphatase)
  • 95% cure rate for stages 1 or 2
Case reports
  • Orchiectomy, radiation therapy (very radiosensitive), cisplatin based chemotherapy for bulky retroperitoneal disease or supradiaphragmatic involvement
Gross description
  • Bulky, homogenous gray white with lobulated and bulging cut surface, usually well demarcated
  • 50% involve entire testis
  • Invasion of tunica albuginea in < 10%
  • Usually no hemorrhage, no cystic change, no extensive necrosis
Gross images

Images hosted on PathOut server:

Contributed by Debra Zynger, M.D.




Images hosted on other servers:

Very large seminoma

Cream colored, soft, fleshy, multinodular tumor


Lobulated soft tan to brown tissue

Soft pink tan nodules

Microscopic (histologic) description
  • Sheets of relatively uniform tumor cells are divided into poorly demarcated lobules by delicate fibrous septa with T lymphocytes and plasma cells
  • Cells are large, round polyhedral with distinct cell membranes, abundant clear / watery cytoplasm (glycogen), large central nuclei, 1 - 2 prominent often elongated and irregular nucleoli
  • Usually minimal mitotic figures
  • Tubular preservation may occur at periphery of tumor
  • 10% have significant NSGCT component
  • Granulomatous inflammation with Langhans type multinucleated giant cells present in 20%
  • Infarction and edema (seen occasionally) simulates microcystic yolk sac tumor
  • Rarely is marked fibrosis, osseous metaplasia (Arch Pathol Lab Med 1993;117:321) or pagetoid spread to rete testis
  • "Anaplastic" terminology is outdated
  • Note: if tumor entirely necrotic, trichrome stain and PLAP may be helpful (Arch Pathol Lab Med 2002;126:205)

  • Seminoma with early carcinomatous transformation: similar to embryonal carcinoma
  • Seminoma with syncytiotrophoblastic giant cells:
    • 10 - 20% of seminomas
    • Giant cells often related to blood vessels
    • No cytotrophoblasts present
    • hCG serum level < 1000 u/L; uncertain if more aggressive behavior
    • Differential diagnosis: granuloma, pleomorphic seminoma cells
  • Tubular seminoma:
    • < 10 cases reported
    • Tumor cells form tubular structures of various sizes and shapes, areas of classic seminoma present, otherwise similar to classic seminoma
    • May resemble yolk sac tumor, embryonal carcinoma, Sertoli cell tumor (use immunohistochemistry to differentiate, Arch Pathol Lab Med 1989;113:414, Am J Clin Pathol 1994;102:397)
Microscopic (histologic) images

Images hosted on PathOut server:

Contributed by Debra Zynger, M.D.

Fibrous bands and lymphocytes

Fried egg appearance

Hilar soft tissue invasion

Epididymal invasion

Discontinuous spermatic cord invasion

Seminoma with IHC





Negative stains
Electron microscopy description
  • Glycogen, annulate lamellae (parallel arrays of cisternae with small annuli or circular fenestrae at regular intervals along their length), disbursed nucleolonema (network of strands)
Back to top