Embryonal sarcoma

Clinical features

  • Usually occurs between 6-10 years of age
  • Presentation: abdominal mass, fever and pain
  • Serum alpha-fetoprotein levels are normal

 

Fig 80 - Embryonal Sarcoma- Cellular smear with mesenchymal clusters in a myxoid matrix (Giemsa)
Fig 81 - Embryonal Sarcoma- Heterogeneous population of neoplastic cells showing atypical cells with bizarre nuclei and lobulated contours. On the bottom a fragment of myxoid tissue (Giemsa)
Fig 82 - Embryonal Sarcoma- stripped bizarre nuclei and necrotic material (H&E)

 

 

  • Cellular smears
  • Mesenchymal clusters
  • Heterogeneous population of tumour cells (spindle, oval, pleomorphic and multinucleated giant cells)
  • Moderate amount of cytoplasm with poorly defined limits
  • Nuclei with coarse chromatin
  • Myxoid background
  • Hyaline globules in the background or intracytoplasmic
  • Haemorrhage and necrosis

 

Immunocytochemistry

  • Anti-chymotrypsin: positive
  • Alpha-1-antitrypsin: positive
  • Desmin: variable
  • Muscle-specific actin: variable
  • Vimentin: variable
  • Alpha-fetoprotein: negative (hyaline globules)
  • Myogenin: negative

 

Genetic studies

Rearrangements of chromosomal band 19q13.4,

t (11; 19) (q13; q13.4)

 

Differential diagnosis

  • Mesenchymal hamartoma
    • In patients under one year of age
    • Bland tumour cells
    • No cellular pleomorphism
  • Embryonal rhabdomyosarcoma
    • No hyaline globules
    • Rhabdomyoblastic differentiation
    • Myogenin : positive
  • Hepatoblastoma (mixed and embryonal)
    • Lack of myxoid stroma
    • Lack of cellular pleomorphism
    • Lack of hyaline globules
    • Presence of extra medullary haematopoiesis

 

Main points

  • Occasionally arising in mesenchymal hamartoma,
  • Primitive mesenchymal neoplasm
  • Treatment: complete surgical resection
  • Death within two years due to direct extension
  • Metastasis to lung and bone
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