Testis

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The Testes are important for survival of the species. Tumours occasionally arise in 'em. They generally are not biopsied. If they are biopsied, it is usually for fertility -- to understand whether they are really azoospermic.

Normal

Seminiferous tubules

  • Sertoli cells (AKA sustentacular cell AKA nurse cell).
    • Large cells with oval nucleus.
  • Primary spermatocyte.
    • Small cells with dark nucleus on basement membrane.
  • Secondary spermatocyte.
    • Rarely seen on light microscopy.
  • Spermatids.
    • Round small.
    • Usually close to the centre of the lumen.
  • Spermatozoa.
    • You don't see the tail on light microscopy.

Interstitium

  • Leydig cell (AKA interstitial cell).
    • Large eosinophilic cell.
  • Blood vessels.

Associated structures

  • Epididymis - stores the sperm.
    • Pseudostratified epithelium with cilia.

Image:

Diagnoses

  • Benign.
    • Spermatid present/not present.
  • Infertility - azoospermic.
    • No sperm present.
  • Germ cell tumours (GCTs).
    • Intratubular germ cell neoplasia.
    • Seminoma.
    • Spermatocytic seminoma.
    • 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).
  • Sex-cord stromal tumour.
    • Leydig cell tumour.
    • Sertoli cell tumour.

IHC for GCTs

ABCDs of GCTs:

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

Intratubular germ cell neoplasia

  • Considered the precursor lesion for germ cell tumours.
  • Not all germ cell tumours (GCTs) arise from intratubular germ cell neoplasia.

The following testicular GCTs do not arise from ITCGN:

Seminoma

Epi. & etiology

  • Arises from intratubular germ cell neoplasia (ITGCN).

Microsopy

Features:

  • Cells with fried egg appearance.
    • Clear cytoplasm.
    • Central nucleus.
      • Nucleus has "corners", i.e. it is not round.
  • Lymphoctyes common, not essential.
  • May see syncytiotrophoblasts.
    • Large + many irregular or lobular hyperchromatic nuclei.
    • Eosinophilic vacuolated cytoplasm (contains hCG).
    • Closest to mom in normal chorionic villi - covers cytotrophoblast.[3]
  • May see florid granulomatous reaction.

Memory device: 3 Cs - clear cytoplasm, central nucleus, corners on the nuclear membrane.

DDx:

  • Mixed germ cell tumour.
  • Solid variant of yolk sac tumour.
    • Lacks fibrous septae and lymphocytes.[4]

IHC

  • D2-40 +ve.
  • CD117 +ve (ckit).
  • CD30 -ve.[5]
    • Done to r/o embryonal carcinoma.
  • Cytokeratins usu. -ve, may have weak focal positivity.[5]

Spermatocytic seminoma

Microscopy[6]

  • Population of three cells.
    • Small cells - look like secondary spermatocytes.
    • Medium cells with nucleoli.
    • Large cells.

Epidemiology

  • Does NOT arise from intratubular germ cell neoplasia (ITGCN)[7] - not considered a subtype of seminoma.

Yolk sac tumour

Tumour also known as endodermal sinus tumour.

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.[8]

Image:

Variants:

  • Hepatoid pattern.[9]
    • Vaguely resembles liver.
      • Hyaline globules (light red well-circumscribed globs).
      • Bile canaculi.
  • Solid pattern.[10]
    • Vaguely resembles seminoma.

Image:

Epidemiology

  • Most common GCT in infants and young boys.

IHC

  • AFP+
  • a1-AT+
  • cytokeratin+ ???

DDx

  • Embryonal carcinoma.


Embryonal carcinoma

General

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

Microscopy

Features:[11]

  • Cell border indistinct.
  • Mitoses common.
  • Variable architecture:
    • Tubulopapillary,
    • Glandular,
    • Solid,
    • Embryoid bodies - ball of cells in surrounded by empty space on three sides.
  • Nuclei overlap.

Notes:

  • Cytoplasmic staining variable (eosinophilic to basophilic).

DDx

  • Yolk sac tumour.

IHC

  • Cytokeratin+ ???[12]
  • CD30+ ???


Choriocarcinoma

Clinical

  • Aggressive clinical course.

Microscopy

  • Syncytiotrophoblasts (eosinophilic cytoplasm with vacuoles (contain hCG), multiple hyperchromatic nuclei)
    • Large + many irreg. or lobular hyperchromatic nuclei
    • Eosinophilic vacuolated cytoplasm (contains hCG)
  • Cytotrophoblasts (polygonal shape, borders, clear cytoplasm, in cords, single nucleus)
    • Polygonal shaped cells in cords/masses
    • Distinct cell borders
    • Clear cytoplasm
    • Single uniform nucleus
  • +/-Hemorrhage
  • +/-Necrosis

Notes:

IHC

  • beta-hCG +ve.

Teratoma

  • Consists of all three germ layers.
    • Endoderm.
    • Mesoderm.
    • Ectoderm.

Classification

  • Divided into:
    • Mature.
    • Immature.

Immature

  • Immature if neural tissue is present:[13]
    • Vaguely resembles pseudostratified respiratory epithelium.

Leydig cell tumour

  • Arises from interstitial cell.
  • AKA interstitial cell tumour.

Microscopic

Features:[14]

  • Vacuolization - key feature.
  • Cytoplasm - clear to eosinophilic.
  • Nucleoli common.
  • Reinke crystals, cylindrical crystalloid eosinophilic cytoplasmic bodies (not always present).

Images:

IHC

  • Inhibin-alpha.
  • Calretinin.[15][16]
  • Melan A.[17]
    • AKA MART-1.
    • Expressed in melanoma, adrenal tissue, steroid-secreting tumours.

Sertoli cell tumour

  • Arises from Sertoli cells (AKA nurse cells).

Microscopic

Features:

  • Groups of cells in chords or trabeculae (beam-like arrangement).
  • Cells have:
    • Light staining bubbly cytoplasm +/- large cytoplasmic vacuoles.
    • Slightly irregular nucleoli.
    • Granular irregular appearing chromatin.

Negatives:

  • Mitoses are rare.
  • No significant nuclear atypia.

Image(s):

See also

References

  1. ↑ Müller J, Skakkebaek NE, Parkinson MC (February 1987). "The spermatocytic seminoma: views on pathogenesis". Int. J. Androl. 10 (1): 147–56. PMID 3583416.
  2. ↑ Manivel JC, Simonton S, Wold LE, Dehner LP (June 1988). "Absence of intratubular germ cell neoplasia in testicular yolk sac tumors in children. A histochemical and immunohistochemical study". Arch. Pathol. Lab. Med. 112 (6): 641–5. PMID 2837162.
  3. ↑ [1]
  4. ↑ URL: http://webpathology.com/image.asp?case=34&n=8. Accessed on: March 8, 2010.
  5. ↑ 5.0 5.1 PMID 16867864.
  6. ↑ 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. ISBN 0-7216-0187-1.
  7. ↑ Müller J, Skakkebaek NE, Parkinson MC (February 1987). "The spermatocytic seminoma: views on pathogenesis". Int. J. Androl. 10 (1): 147–56. doi:10.1111/j.1365-2605.1987.tb00176.x. PMID 3583416.
  8. ↑ URL: http://webpathology.com/image.asp?case=34&n=1. Accessed on: March 8, 2010.
  9. ↑ URL: http://webpathology.com/image.asp?case=34&n=6. Accessed on: March 8, 2010.
  10. ↑ URL: http://webpathology.com/image.asp?case=34&n=8. Accessed on: March 8, 2010.
  11. ↑ GUP P.549
  12. ↑ NEED REF.
  13. ↑ RS. 2 May 2010.
  14. ↑ GUP P.581.
  15. ↑ URL: http://www.antibodybeyond.com/reviews/cell-markers/leydig-cell-marker.htm. Accessed on: 18 May 2010.
  16. ↑ PMID 15950053.
  17. ↑ PMID 12966351.

External links

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