Germ cell tumours

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This article covers germ cell tumours which classicaly arise in the gonads (ovary, testis). They also show-up in neuropathology and in the mediastinum.

Germinoma

Comes in three flavours:

  • Germinoma.
  • Seminoma.
  • Dysgerminoma.

Germinoma

Is the generic version of this tumour. It is found in the midline (brain, mediastinum).

Seminoma

A common GCT in males.

Dysgerminoma

A common GCT in females.

Yolk sac tumour

General

  • Tumour also known as endodermal sinus tumour.

Epidemiology

  • Most common GCT in infants and young boys.

Microscopy

Classic feature:

  • Schiller-Duval bodies.
    • Look like glomerulus - central blood vessel surrounded by epithelial-like cells a space and more epithelial-like cells
  • Architecure - variable.
    • Most common microcystic pattern.[1]

Image:

Variants:

  • Hepatoid pattern.[2]
    • Vaguely resembles liver.
      • Hyaline globules (light red well-circumscribed globs).
      • Bile canaculi.
  • Solid pattern.[3]
    • Vaguely resembles seminoma.

Image:

IHC

  • AFP +ve.
  • Glypican 3 +ve.
    • More sensitive than AFP.[4]
  • Alpha-1 AT +ve.
  • Cytokeratin +ve. ???

DDx

  • Embryonal carcinoma.

Embryonal carcinoma

General

  • Affects young adults.
    • May be seen in women.

Microscopic

Features:[5]

  1. Nucleoli - key feature.
  2. Vesicular nuclei (clear, empty appearing nuclei) - key feature.
  3. Nuclei overlap.
  4. Necrosis - common.
    • Not commonly present in seminoma.
  5. Indistinct cell borders
  6. Mitoses - common.
  7. Variable architecture:
    • Tubulopapillary.
    • Glandular.
    • Solid.
    • Embryoid bodies - ball of cells in surrounded by empty space on three sides.

Notes:

  • Cytoplasmic staining variable (eosinophilic to basophilic).

Images:

DDx

  • Yolk sac tumour.

IHC

  • AE1/AE3 +ve.
  • CD30 +ve.

Choriocarcinoma

General

  • Aggressive clinical course.

Microscopic

Features:

  • Cytotrophoblasts - key feature.
    • Clear cytoplasm.
    • Polygonal shaped cells in cords/masses.
    • Distinct cell borders.
    • Single uniform nucleus.
  • +/-Hemorrhage.
  • +/-Necrosis.
  • Syncytiotrophoblasts - may be absent.[6]
    • Large + many irreg. or lobular hyperchromatic nuclei.
    • Eosinophilic vacuolated cytoplasm (contains hCG).

Image(s):

Notes:

IHC

  • beta-hCG +ve.

Teratoma

General

  • Consists of all three germ layers:[7]
    1. Endoderm:
      • Skin, CNS.
    2. Mesoderm:
      • Muscle, bone, connective tissue, blood.
    3. Ectoderm:
      • Internal organs.

Classification

  • Divided into:
    • Mature.
    • Immature.

Immature

  • Immature if neural tissue is present:[8]
    • Vaguely resembles pseudostratified respiratory epithelium.
  • Islands of small hyperchromatic cells - "blastema".
  • +/-Cartilage.
  • +/-Adipocytes.
  • +/-Colonic type mucosa.
  • +/-Stratified squamous epithelium (skin).

Images:

Other images:

Grading

Based on quantity of immature neuroepithelium:[9][10][11]

  • G0 - mature teratoma; no immature neuroepithelium.
  • G1 - less than one lower power field (LPF) of immature neuroepithelium; LPF defined field at 4X magnification.
  • G2 - 1-3 LPFs.
  • G3 - more than 3 LPFs.

Note:

  • LPF not adequately defined - see LPFitis. Same BS as HPF.

IHC (immature)

Features:

  • Primitive neuroepithelium:[12]
    • Neuron-specific enolase (NSE) +ve.
    • Neuron-specific B tubulin +ve.
    • Synaptophysin +ve.

See also

References

  1. URL: http://webpathology.com/image.asp?case=34&n=1. Accessed on: March 8, 2010.
  2. URL: http://webpathology.com/image.asp?case=34&n=6. Accessed on: March 8, 2010.
  3. URL: http://webpathology.com/image.asp?case=34&n=8. Accessed on: March 8, 2010.
  4. Emerson, RE.; Ulbright, TM. (Jun 2010). "Intratubular germ cell neoplasia of the testis and its associated cancers: the use of novel biomarkers.". Pathology 42 (4): 344-55. doi:10.3109/00313021003767355. PMID 20438407.
  5. Zhou, Ming; Magi-Galluzzi, Cristina (2006). Genitourinary Pathology: A Volume in Foundations in Diagnostic Pathology Series (1st ed.). Churchill Livingstone. pp. 549. ISBN 978-0443066771.
  6. URL: http://www.webpathology.com/image.asp?n=4&Case=36. Accessed on: 8 February 2011.
  7. Moore, Keith L.; Persaud, T.V.N. (2002). The Developing Human: Clinically Oriented Embryology (7th ed.). Saunders. pp. 83. ISBN 978-0721694122.
  8. RS. 2 May 2010.
  9. Harms D, Zahn S, Göbel U, Schneider DT (2006). "Pathology and molecular biology of teratomas in childhood and adolescence". Klin Padiatr 218 (6): 296–302. doi:10.1055/s-2006-942271. PMID 17080330.
  10. Ulbright TM (February 2005). "Germ cell tumors of the gonads: a selective review emphasizing problems in differential diagnosis, newly appreciated, and controversial issues". Mod. Pathol. 18 Suppl 2: S61–79. doi:10.1038/modpathol.3800310. PMID 15761467. http://www.nature.com/modpathol/journal/v18/n2s/full/3800310a.html.
  11. O'Connor DM, Norris HJ (October 1994). "The influence of grade on the outcome of stage I ovarian immature (malignant) teratomas and the reproducibility of grading". Int. J. Gynecol. Pathol. 13 (4): 283–9. PMID 7814189.
  12. Craver RD, Lipscomb JT, Suskind D, Velez MC (October 2001). "Malignant teratoma of the thyroid with primitive neuroepithelial and mesenchymal sarcomatous components". Ann Diagn Pathol 5 (5): 285–92. doi:10.1053/adpa.2001.27918. PMID 11598856.