Germinoma/seminoma

Clinical features

  • Generally in adolescents
  • The least aggressive of the malignant germ cell tumours in children
  • Found in the ovary and pineal region
  • Testicular tumours are rare at this age
  • Rarely as a component of a teratoma
  • 15% bilateral (in patients with gonadal dysgenesis)
  • Serum elevation of lactic dehydrogenase and isoenzyme-1

 

Fig 66 – Germinoma – High cellular smear composed of large single cells with abundant cytoplasm admixed with lymphocytes. Tigroid background (Giemsa)
Fig 67a – Germinoma –Large single cells with unique central vesicular nuclei and with prominent nucleoli. Lymphocytes are abundant (H&E). Remark in b) the presence of epithelioid granulomas.
Fig 67b – Germinoma –Large single cells with unique central vesicular nuclei and with prominent nucleoli. Lymphocytes are abundant (H&E). Remark in b) the presence of epithelioid granulomas.
Fig 68 - Germinoma –Tigroid background (Giemsa)

 

  • Moderately to highly cellular smears
  • Poorly cohesive cells
  • Stripped nuclei
  • Large single cells with single central vesicular nuclei and prominent nucleoli
  • Fragile cytoplasm (glycogen)
  • Tigroid background (Giemsa stain); absent in the atypical forms
  • Epithelioid cells, occasionally granulomas
  • Multinucleated histiocytic cells
  • Lymphocytes (rare in the atypical forms)
  • Necrosis is not characteristic

 

Histochemical stains

  • PAS positive; PAS-diastase negative

 

Immunocytochemistry) (see Table 1)

  • Placental alkaline phosphatase (PLAP): positive
  • Vimentin: positive
  • CD117: positive
  • OCT4: positive
  • Cytokeratin: generally negative (some authors have reported that 15% of cases are positive)
  • EMA: negative
  • Alpha-fetoprotein: negative

 

Differential diagnosis

  • Large cell lymphoma
    • Lymphoglandular bodies
    • More irregular nuclei
    • Lacks glycogen
    • CD45: positive
    • PLAP: negative
  • Embryonal carcinoma
    • Carcinoma pattern (acinar, tubular, papillary or solid)
    • Prominent cellular polymorphism
    • Nuclei with coarse chromatin and multiple nucleoli
    • Necrosis
    • Absence of lymphocytes
    • Absence of tigroid background
    • CD30: positive
    • Cytokeratin: positive
    • CD117: negative

 

Main points

  • Five-year survival for pure forms is 80-90%
  • Metastasizes to the opposite ovary, retroperitoneal nodes and peritoneal cavity
  • Generally occurs as pure forms
  • Association with choriocarcinoma, yolk sac tumour or embryonal carcinoma worsens the prognosis
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