Clinical features
- Peak incidence in the first decade
- Pure forms are rare in children
- More common in the testis than in the ovary
- High serum human chorionic gonadotropin (HCG)
- Less commonly elevated serum alpha-fetoprotein
- Isosexual precocity: vaginal bleeding, amenorrhea, hirsutism
Fig 73 – Embryonal carcinoma – Cohesive group of pleomorphic tumor cells, with moderate amount of vacuolated cytoplasm. Necrosis in the background (Giemsa)
- Cellular smears
- Similar appearance to an adenocarcinoma:
- Sheets, nests, glandular or papillary formations
- Ragged-edged cell clusters
- Large pleomorphic cells
- Irregular nuclei
- Coarse chromatin
- Multiple prominent nucleoli
- Sparse cytoplasm
- Syncytiotrophoblast cells
- Necrotic background
Immunocytochemistry (see Table 1)
- Cytokeratin: positive
- CD30: positive
- Alpha-fetoprotein: positive (focal)
- OCT4: positive
- PLAP: positive (focal in syncytiotrophoblast cells)
- EMA: Negative
Modern diagnostic techniques
- Non-contributory
Differential diagnosis
- Germinoma
- Poorly cohesive cells
- More monotonous population
- Nuclei with clear chromatin and single nucleoli
- Cytoplasmic glycogen vacuoles
- Tigroid background
- Lymphocytes
- Placental alkaline phosphatase (PLAP): positive
- CD117:positive
- Cytokeratin: usually negative
- EMA: negative
- CD30: negative
- Carcinoma
- Rare in children
- CD30: negative
- Yolk sac tumour
- Mucoid background
- Less necrosis
- Smaller cells
- Intra and extra cytoplasmic hyaline globules
- Dense basement membrane-like matrix associated with neoplastic cells
- Alpha-fetoprotein: positive (intense)
- CD30:negative
Table 1- Immunophenotype of germ cell tumours
| Marker: | Seminoma | Yolk sactumour | Embryonalcarcinoma | Choriocarcinoma |
| AE1/AE3) | +/- | + | + | + |
| PLAP | + | + | + | +/- |
| AFP | – | + | +/- | – |
| Beta-HCG | – (except in giant cells) | – | – | + |
| S-100 protein | – | – | – | – |
| LCA | – | – | – | – |
| CD30 | – (rarely +) | – | + | – |
| OCT4 | + | – | + | – |
AFP-alpha-fetoprotein; CK- cytokeratin; HCG- human chorionic gonadotropin; LCA- leukocyte common antigen; PLAP- placenta-like alkaline phosphatase; + positive; +/- positive or negative; – negative.