Mixed germ cell tumour

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Mixed germ cell tumour, abbreviated MGCT, is a lesion composed of different germ cell tumours. Most germ cell tumours are mixed.

Mixed germ cell tumour
Diagnosis in short

Mixed germ cell tumour. H&E stain.
LM depends on the components
LM DDx other germ cell tumours
IHC variable
Gross heterogeneous appearance, typically solid and cystic
Grossing notes orchiectomy
Site ovary, testis, mediastinum, other
Signs mass lesion
Prevalence most common germ cell tumour
Blood work +/-AFP elevated, +/-beta-hCG elevated, +/-LDH elevated
Prognosis worse than seminoma/dysgerminoma
Clin. DDx gonads: germ cell tumours, other tumours

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.

Note:

  • † Numbers vary between sources. One series suggests it is almost 70%.[1]
  • There has been in increase in MGCTs over the past 20 years that is probably due to changes how in how GCTs are classified.[2]

Gross

  • Heterogeneous appearance - distinctive regions that look different from one another.
  • Typically solid and cystic.

Images

  • Mixed germ cell tumour. (WC/euthman)

Microscopic

Features:

  • Depends on the components.
  • Classic appearances:
    • Seminoma: fried egg-like" cells with lymphocytes.
    • Yolk sac tumour: edematous appearing/paucicellular regions, Schiller-Duval bodies.
    • Embryonal carcinoma: moderate-to-marked nuclear atypia with overlapping nuclei and usu. necrosis.
    • Teratoma: cysts with GI like epithelium, cysts with squamous epithelium & keratin (skin), immature cartilage, others.
    • Choriocarcinoma: hemorrhagic, multinucleated cells (syncytiotrophoblasts) and cells with pale cytoplasm (cytotrophoblasts).

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

  • Immunostains are useful for differentiating components, e.g. yolk sac tumour versus embryonal carcinoma.

Looking for elements

  • Beta-hCG +ve - if syncytiotrophoblasts are present.
  • AFP +ve (or Glypican 3 +ve) - a yolk sac tumour component is present.
  • GFAP +ve - if neuroepithelium is present.

A panel:

  • CD30 +ve -- embryonal carcinoma.
  • OCT4 +ve -- seminoma.
  • D2-40 +ve -- seminoma, useful for LVI.
  • Pankeratin +ve -- embryonal carcinoma.
  • CEA-M.
  • EMA +ve -- metastatic carcinoma.[3]
  • Vimentin.
  • Glypican 3 +ve -- yolk sac tumour.
    • Others: A1A +ve -- yolk sac tumour, AFP +ve -- yolk sac tumour.

Sign out

TESTIS, RIGHT, ORCHIECTOMY:
- MALIGNANT MIXED GERM CELL TUMOUR, pT1 pNx:
-- 80% OF TUMOUR TERATOMA.
-- 20% OF TUMOUR SEMINOMA.
-- PLEASE SEE TUMOUR SUMMARY.

See also

References

  1. ↑ Mosharafa, AA.; Foster, RS.; Leibovich, BC.; Ulbright, TM.; Bihrle, R.; Einhorn, LH.; Donohue, JP. (Apr 2004). "Histology in mixed germ cell tumors. Is there a favorite pairing?". J Urol 171 (4): 1471-3. doi:10.1097/01.ju.0000116841.30826.85. PMID 15017200.
  2. ↑ Trabert, B.; Stang, A.; Cook, MB.; Rusner, C.; McGlynn, KA. (Aug 2011). "Impact of classification of mixed germ-cell tumours on incidence trends of non-seminoma.". Int J Androl 34 (4 Pt 2): e274-7. doi:10.1111/j.1365-2605.2011.01187.x. PMID 21623833.
  3. ↑ Shek, TW.; Yuen, ST.; Luk, IS.; Wong, MP. (Mar 1996). "Germ cell tumour as a diagnostic pitfall of metastatic carcinoma.". J Clin Pathol 49 (3): 223-5. PMID 8675733.
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