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 tumours (GCTs).
    • Intratubular germ cell neoplasia.
    • Germinoma/Seminoma/Dysgerminoma.
    • Yolk sac tumour (endodermal sinus tumour).
    • Embryonal carcinoma.
    • Choriocarcinoma.
    • Teratoma.
    • Mixed GCT - 60% of GCTs are mixed.
      • Common combinations:
        1. teratoma + embryonal carcinoma + endodermal sinus tumour (yolk sac tumour) (TEE).
        2. seminoma + embryonal (SE).
        3. embryonal + teratoma (TE).

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[1] 		CD117 appearance similar to seminoma [1], [2]
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[2] 		D2-40 seminoma = male version of this tumour; dysgerminoma = female version of this tumour [3], [4]
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 hepatoid YST
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 [5], [6], [7]
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 [8], [9]
Teratoma, immature primitive neuroepithelium pseudostratified epithelium in rosettes (gland-like arrangement) None teratoma are always malignant in males [10]
Mixed germ cell tumour NA common combinations: teratoma + embryonal carcinoma + endodermal sinus tumour (yolk sac tumour) (TEE); seminoma + embryonal (SE); embryonal + teratoma (TE) NA - [11]
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 [12]

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).[3]

Seminoma

Main article: Testis#Seminoma

A common GCT in males.

Dysgerminoma

Main article: Ovarian tumours#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.

Microscopic

Classic feature:[4]

  • Schiller-Duval bodies.
    • Look like glomerulus - central blood vessel surrounded by epithelial-like cells a space and more epithelial-like cells
  • Architecure - variable.
    1. Reticular - most common according to WMSP.[5]
    2. Microcystic - most common according to webpathology.com.[6]
      • Lace-like pattern.
    3. Endodermal sinus-like - has Schiller-Duval bodies.
    4. Solid.
    5. Papillary.
    6. Glandular.
    7. Alveolar.
    8. Enteric.
    9. Polyvesicular vitelline.
    10. Hepatoid.
  • +/-Eosinophilic hyaline globules (contain alpha-fetoprotein).

Notes:

  • Has a loose stroma/vaguely discohesive -- unlike embryonal carcinoma.

Variants:

  • Hepatoid pattern.[7]
    • Vaguely resembles liver.
  • Solid pattern.[8]
    • Vaguely resembles seminoma.

Images:

IHC

  • AFP +ve.
  • Glypican 3 +ve.
    • More sensitive than AFP.[9]
  • Alpha-1 AT +ve.
  • Cytokeratin +ve. ???

DDx

  • Embryonal carcinoma.

Embryonal carcinoma

General

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

Microscopic

Features:[10]

  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.
  • Usually a mixed tumour, i.e. pure choriocarcinoma is rare, e.g. dysgerminoma + choriocarcinoma.

Clinical/Epidemiology

  • High beta-hCG.
  • May be preceded by a complete hydatidiform mole.[11]
  • More common in the far east.
  • More common at extremes of fertile age (teens and 40-50 years).

Microscopic

Features:

  • Two cell populations:
  1. Cytotrophoblasts - key feature.
    • Clear cytoplasm.
    • Polygonal shaped cells in cords/masses.
    • Distinct cell borders.
    • Single uniform nucleus.
  2. Syncytiotrophoblasts - may be absent.[12]
    • Large + many irreg. or lobular hyperchromatic nuclei.
    • Eosinophilic vacuolated cytoplasm (contains hCG).
  • +/-Hemorrhage.
  • +/-Necrosis.

Notes:

  • No chorionic villi should be present.
  • The dual cell population may not be evident at first.
    • Hemorrhage and marked nuclear pleomorphism are suggestive of the diagnosis.

Images:

IHC

  • beta-hCG +ve.
    • Classically said to be produced by syncytiotrophoblasts.[14]
      • Cytotrophoblasts also produce some.[14][15]

Teratoma

General

  • May be benign or malignant.
  • Are supposed to consists of all three germ layers - this is not always true.
  • May be associated with sacral agenesis.[16]

Classification

  1. Mature.
    • Common in females.
    • Usually benign; however, mature component may give rise to a malignancy like elsewhere in the body.
  2. Immature.
    • Uncommon.
    • Malignant.
  3. Monodermal.
    • Rare.
    • Highly specialized.

Mature teratoma

Features - three germ cell layers (usually):[17]

    1. Endoderm:
      • Skin, (mature) CNS.
    2. Mesoderm:
      • Muscle, bone, connective tissue, blood.
    3. Ectoderm:
      • Internal organs.

Note:

  • May consist of skin only - in which case it is commonly called a dermoid.

Images:

Immature teratoma

Features:

  • Immature if neural tissue is present:[18]
    • Vaguely resembles pseudostratified respiratory epithelium.
  • Islands of small hyperchromatic cells - "blastema".
  • +/-Cartilage.
  • +/-Adipocytes.
  • +/-Colonic type mucosa.
  • +/-Stratified squamous epithelium (skin).

Images:

Other images:

Grading (immature)

Based on quantity of immature neuroepithelium:[19][20][21]

  • 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:[22]
    • Neuron-specific enolase (NSE) +ve.
    • Neuron-specific B tubulin +ve.
    • Synaptophysin +ve.

Monodermal teratomas

Struma ovarii

Features:

Images:

Strumal carcinoid

Features:[23][24]

  • Has components that suggest:
    1. Carcinoid (neuroendocrine tumour).
      • Nuclei with stippled chromatin (salt-and-pepper chromatin).
    2. Thyroid - cystic spaces/follicular-like structures.

Images:

Gonadoblastoma

General

  • Associated with abnormal sexual development.
  • Often coexist with a dysgerminoma.
  • A mixed tumour that consists of (1) primitive germ cells and (2) sex cord elements.

Gross

  • +/-Cystic.

Microscopic

Features:[25]

  • Immature germ cells resembling Sertoli cells or granulosa cells.
    • Sertoli cells = moderate cytoplasm in a trabecular or tubular architecture.
    • Granulosa cells = form follicle-like structures.
      • May form nests.
  • Primitive germ cells resemble those of a dysgerminoma.
    • Polygonal cells with a central nucleus, squared-off nuclear membrane and clear cytoplasm.
  • +/-Calcification (very common).
  • +/-Eosinophilic basement membrane material between the (primitive) germ cells and support cells.[26]

Images:

Polyembryoma

General

  • Poor prognosis.
  • Almost never in pure form, i.e. usu. a component of a mixed germ cell tumour.[27]

Microscopic

Features:

  • Embryo like-structure:
    • Disc shaped structure - one side endoderm, other side ectoderm.

Image:

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:

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. ↑ 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.
  2. ↑ 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.
  3. ↑ URL: http://path.upmc.edu/cases/case525.html. Accessed on: 25 January 2012.
  4. ↑ Mitchell, Richard; Kumar, Vinay; Fausto, Nelson; Abbas, Abul K.; Aster, Jon (2011). Pocket Companion to Robbins & Cotran Pathologic Basis of Disease (8th ed.). Elsevier Saunders. pp. 510. ISBN 978-1416054542.
  5. ↑ Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 369. ISBN 978-0781765275.
  6. ↑ URL: http://webpathology.com/image.asp?case=34&n=1. Accessed on: March 8, 2010.
  7. ↑ URL: http://webpathology.com/image.asp?case=34&n=6. Accessed on: March 8, 2010.
  8. ↑ URL: http://webpathology.com/image.asp?case=34&n=8. Accessed on: March 8, 2010.
  9. ↑ 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.
  10. ↑ 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.
  11. ↑ Cotran, Ramzi S.; Kumar, Vinay; Fausto, Nelson; Nelso Fausto; Robbins, Stanley L.; Abbas, Abul K. (2005). Robbins and Cotran pathologic basis of disease (7th ed.). St. Louis, Mo: Elsevier Saunders. pp. 1110-1111. ISBN 0-7216-0187-1.
  12. ↑ URL: http://www.webpathology.com/image.asp?n=4&Case=36. Accessed on: 8 February 2011.
  13. ↑ Venkatram, S.; Muppuri, S.; Niazi, M.; Fuentes, GD. (Jul 2010). "A 24-year-old pregnant patient with diffuse alveolar hemorrhage.". Chest 138 (1): 220-3. doi:10.1378/chest.09-2688. PMID 20605823.
  14. ↑ 14.0 14.1 Cole, LA. (2010). "Biological functions of hCG and hCG-related molecules.". Reprod Biol Endocrinol 8: 102. doi:10.1186/1477-7827-8-102. PMC 2936313. PMID 20735820. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2936313/.
  15. ↑ Kovalevskaya, G.; Genbacev, O.; Fisher, SJ.; Caceres, E.; O'Connor, JF. (Aug 2002). "Trophoblast origin of hCG isoforms: cytotrophoblasts are the primary source of choriocarcinoma-like hCG.". Mol Cell Endocrinol 194 (1-2): 147-55. PMID 12242037.
  16. ↑ Online 'Mendelian Inheritance in Man' (OMIM) 176450
  17. ↑ Moore, Keith L.; Persaud, T.V.N. (2002). The Developing Human: Clinically Oriented Embryology (7th ed.). Saunders. pp. 83. ISBN 978-0721694122.
  18. ↑ RS. 2 May 2010.
  19. ↑ 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.
  20. ↑ 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.
  21. ↑ 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.
  22. ↑ 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.
  23. ↑ Gorin, I.; Sastre-Garau, X. (Jun 2008). "Strumal carcinoid tumor of the ovary.". J Clin Oncol 26 (16): 2780-1. doi:10.1200/JCO.2008.16.1620. PMID 18509188.
  24. ↑ Tamsen, A.; Mazur, MT. (Feb 1992). "Ovarian strumal carcinoid in association with multiple endocrine neoplasia, type IIA.". Arch Pathol Lab Med 116 (2): 200-3. PMID 1346363.
  25. ↑ Cotran, Ramzi S.; Kumar, Vinay; Fausto, Nelson; Nelso Fausto; Robbins, Stanley L.; Abbas, Abul K. (2005). Robbins and Cotran pathologic basis of disease (7th ed.). St. Louis, Mo: Elsevier Saunders. pp. 1104. ISBN 0-7216-0187-1.
  26. ↑ URL: http://www.flickr.com/photos/ckrishnan/3972432044/in/photostream/. Accessed on: 11 September 2011.
  27. ↑ 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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