CNS tumor
Germ cell tumors

Topic Completed: 1 January 2006

Revised: 6 September 2017, last major update January 2006

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

PubMed Search: Germinoma [title] CNS

Nat Pernick, M.D.
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Cite this page: Pernick N. Germinoma. website. Accessed May 30th, 2020.
Definition / general
  • Most common intracranial germ cell neoplasm
  • Often teenagers and young adults
  • 2/3 male
  • May be mixed with other germ cell tumors
  • May derive from ectopic rests, transformation of resident germ cells or migration of germ cells late in development
  • Most common site is pineal region
  • Also anterior or posterior third ventricle, rarely fourth ventricle
  • Rarely associated with dysgenetic syndromes
  • Immunostains useful because biopsy is often small
  • Relatively good prognosis (5 - 10 year survival is 75 - 95%) vs. 25 - 40% for nongerminoma germ cell tumors (Pediatr Neurol 2002;26:369)
  • Very sensitive to radiotherapy and chemotherapy - nongerminomatous germ cell tumors are less radiosensitive
  • Metastases may be due to surgical displacement of tumor
  • Spinal cord metastases occur in 10 - 15% of patients
Staging / staging classifications
  • T1: smaller than 5 cm in diameter and located in the suprasellar, intrasellar or pineal region
  • T2: larger than 5 cm in diameter and located in the perisellar region
  • T3: may be smaller than 5 cm in diameter but invades and encroaches on the third ventricle
  • T4: extends into the anterior, middle or posterior fossa

  • N: not indicated for CNS tumors

  • M0: no evidence of gross subarachnoid or hematogenous metastasis
  • M1: microscopic tumor cells found in the CSF
  • M2: gross nodular seeding in the ventricular system or cranial subarachnoid spaces
  • M3: gross nodular seeding in the spinal subarachnoid spaces
  • M4: metastasis outside the cerebrospinal axis
Case reports
  • Resection difficult due to high collagen content
  • Radiation therapy helpful
Gross description
  • Soft, gray pink, homogenous
  • Variable encapsulation
  • Usually poorly circumscribed and infiltrative
Microscopic (histologic) description
  • Resembles seminoma / dysgerminoma
  • Large, epithelioid cells with abundant PAS+ cytoplasm, large, round nuclei and irregular and pleomorphic nuclei
  • May have prominent nests of lymphocytes with occasional granulomatous inflammation that may obscure tumor cells (Neurol Med Chir (Tokyo) 2005;45:415)
  • Lymphocytes may smear in small biopsies
  • Frequent mitotic activity and necrosis
  • Syncytiotrophoblasts in 14%
  • Less anaplasia than embryonal carcinoma
  • No cells intermediate in size between lymphocytes and large germinoma cells
Microscopic (histologic) images

Images hosted on other servers:

Large glycogen rich cells with clear cytoplasm

Germinoma - pineal gland

Infiltration of optic nerve

Various images

Cytology description
  • Loose fragments or single large pleomorphic and polygonal cells with vacuolated cytoplasm, enlarged oval nuclei and prominent nucleoli
  • Frequent mitotic figures, naked nuclei, foamy background
  • Also smashed lymphoid cells with streaking
Cytology images

Images hosted on other servers:

Large pleomorphic
cells with

Positive stains
Negative stains
Electron microscopy description
  • Glycogen in cytoplasm, sparse cytoskeletal elements, prominent nucleoli
Electron microscopy images

Images hosted on other servers:

Cytoplasmic glycogen and prominent nucleoli

Differential diagnosis
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