Germ cell tumours

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This article covers germ cell tumours, often abbreviated GCT, which classically arise in the gonads (ovary, testis). They are also found in the midline and make appearances in neuropathology (e.g. pineal gland) and in the mediastinum.

Overview

Germ cell tumour - types

Precusor:

Germ cell tumours (GCTs):

Grossing

  • 1 cm^2 of tumour per cm of maximal tumour dimension - guideline for testicular cancer.[1]

IHC for GCTs

ABCDs of GCTs:

  • AFP - yolk sac tumour.
  • Beta-hCG - choriocarcinoma.
  • CD30 - embryonal carcinoma.
  • D2-40 - seminoma.

Tabular summary of GCTs

Tumour Key feature Microscopic IHC Other Image
Intratubular germ cell neoplasia (ITGCN) nests of small fried egg cells large central nucleus, clear
cytoplasm, squared-off nuclear membrane, nucleoli[2] 		CD117 appearance similar to seminoma
ITGCN (WC/Nephron)
Germinoma / Seminoma / Dysgerminoma fried egg cells fried egg-like cells (central nucleus, clear
cytoplasm) with squared-off nuclear
membrane, nucleoli, lymphocytic infiltrate, granulomata,
syncytiotrophoblastic giant cells[3] 		D2-40 seminoma = male version of this tumour; dysgerminoma = female version of this tumour
Seminoma (WC/Nephron)
Yolk sac tumour (endodermal sinus tumour) Schiller-Duval bodies Schiller-Duval b. = central blood vessel surrounded by epithelial-like cells a space and more epithelial-like cells, variable arch. AFP patterns: microcystic, solid, hepatoid
Yolk sac tumour (WC)
Embryonal carcinoma prominent nucleoli, vescicular nuclei var. arch.: tubulopapillary, glandular, solid, embryoid bodies (ball of cells in surrounded by empty space on three sides), +/-nuclear overlap, mitoses common CD30 usu. part of a mixed GCT
Embryonal carcinoma (WC/Nephron)
Choriocarcinoma clear cytoplasm cells with abundant clear cytoplasm and eccentric atypical nuclei (cytotrophoblast), very large (multinucleated) cells with abundant eosinophilic cytoplasm and extreme nuclear atypia (syncytiotrophoblast) beta-hCG may be preceded by a complete hydatidiform mole
Choriocarcinoma. (WC/Nephron)
Teratoma, immature primitive neuroepithelium pseudostratified epithelium in rosettes (gland-like arrangement) None testicular teratomas in post-pubertal males are all considered malignant[4]
Primitive neuroepithelium (WC/Nephron)
Mixed germ cell tumour NA common combinations: teratoma + embryonal carcinoma + endodermal sinus tumour (yolk sac tumour) (TEE); seminoma + embryonal (SE); embryonal + teratoma (TE) NA -
Mixed GCT (WC/Nephron)
Gonadoblastoma primitive germ cells (central nucleus, moderate (eosinophilic) cytoplasm); sex cord element sex cord element may be either granulosa cells (follicle-like arch.) or Sertoli cells (trabecular arch.) ? often abnormal karyotype; usu. Y chromosome present
Gonadoblastoma (WC/Nephron)

Molecular pathology

Most common cytogenetic abnormality in GCTs:

  • Isochromosome p12.[5]
    • Isochromosome = one arm (p or q) is lost and replaced with a duplicate of the remaining one.
      • Example: isochromosome p12 = chromosome 12 where q is lost and two p arms are present.[6]

Germinoma

Comes in three flavours:

  • Germinoma.
  • Seminoma.
  • Dysgerminoma.

Germinoma

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

Image: Germinoma (upmc.edu).[7]

Seminoma

Main article: Seminoma

A common GCT in males.

Dysgerminoma

Main article: Ovarian tumours#Dysgerminoma

A common GCT in females.

Yolk sac tumour

Main article: Yolk sac tumour

Embryonal carcinoma

Main article: Embryonal carcinoma

Choriocarcinoma

Main article: Choriocarcinoma

Teratoma

Main article: Teratoma

Gonadoblastoma

Main article: Gonadoblastoma

Polyembryoma

General

Microscopic

Features:

  • Disc shaped structure (embryo-like) with:
    • The one side endoderm.
      • Skin/CNS.
    • The other side ectoderm.
      • Internal organs - GI tract.

Images:

Mixed germ cell tumour

General

  • 60% of GCTs are mixed.

Common combinations:

  1. Teratoma + embryonal carcinoma + endodermal sinus tumour (yolk sac tumour) (TEE).
  2. Seminoma + embryonal (SE).
  3. Teratoma + embryonal +(TE).

Memory device: TEE + all combinations have embryonal carcinoma.

Microscopic

Features:

  • Depends on components.

Notes:

  • If one cannot identify the component... it is probably yolk sac as this has so many different patterns.

Images

  • Mixed GCT - intermed mag. (WC/Nephron)

  • Mixed GCT - high mag. (WC/Nephron)

www:

IHC

  • Beta-hCG +ve - if syncytiotrophoblasts are present.
  • AFP +ve - a yolk sac tumour component is present.
  • GFAP +ve - if neuroepithelium is present.

See also

References

  1. ↑ URL: http://www.uroweb.org/gls/pdf/10_Testicular_Cancer.pdf. Accessed on: 30 October 2012.
  2. ↑ Zhou, Ming; Magi-Galluzzi, Cristina (2006). Genitourinary Pathology: A Volume in Foundations in Diagnostic Pathology Series (1st ed.). Churchill Livingstone. pp. 538. ISBN 978-0443066771.
  3. ↑ Zhou, Ming; Magi-Galluzzi, Cristina (2006). Genitourinary Pathology: A Volume in Foundations in Diagnostic Pathology Series (1st ed.). Churchill Livingstone. pp. 542. ISBN 978-0443066771.
  4. ↑ Carver, BS.; Al-Ahmadie, H.; Sheinfeld, J. (May 2007). "Adult and pediatric testicular teratoma.". Urol Clin North Am 34 (2): 245-51; abstract x. doi:10.1016/j.ucl.2007.02.013. PMID 17484929.
  5. ↑ Looijenga, LH.; Oosterhuis, JW. (May 1999). "Pathogenesis of testicular germ cell tumours.". Rev Reprod 4 (2): 90-100. PMID 10357096.
  6. ↑ URL: http://ghr.nlm.nih.gov/handbook/illustrations/isochromosomes. Accessed on: 15 February 2012.
  7. ↑ URL: http://path.upmc.edu/cases/case525.html. Accessed on: 25 January 2012.
  8. ↑ Young, RH. (Apr 2008). "Testicular tumors--some new and a few perennial problems.". Arch Pathol Lab Med 132 (4): 548-64. doi:10.1043/1543-2165(2008)132[548:TTNAAF]2.0.CO;2. PMID 18384207.
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