Testis and epididymis
Germ cell tumors

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

Revised: 20 July 2017, last major update January 2013

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

PubMed Search: Seminoma testis [title]

Cite this page: Seminoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/testisseminomas.html. Accessed July 21st, 2018.
Definition / general
  • Also called classic seminoma
  • 30 - 50% of testicular germ cell tumors
  • Mean age 40 years vs. 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 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 other servers:

Normal testis on left, seminoma on right

Histologic pattern of typical seminoma

Interstitial growth pattern

Diffuse sheets of tumor cells

Lymphocytic infiltrate in fibrous trabeculae

Lymphocytic infiltrate
surrounding clusters
of tumor cells

Cytoplasm of seminoma cells

Florid lymphoid reaction

Tumor cells infiltrate interstitium

Large and small ghostlike necrotic cells



Contributed by: Dr. Semir Vranic, University of Sarajevo (Bosnia)

Positive stains
Negative stains
  • Cytokeratin (may be weak / focal; syncytiotrophoblastic giant cells are positive), AFP, hCG (syncytiotrophoblastic giant cells are positive), CD30, EMA
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)