Mature teratoma is not a cytological diagnosis. The presence of an immature or malignant component in a tumour cannot be ruled out through FNA.

Clinical features

  • Mature tumours in children are mostly cystic (dermoid cyst)
  • Bilateral in 15%


Fig 63 – Teratoma –Testicular teratoma - Adipose cells, epithelial cylindrical cells and a three-dimensional group of poorly differentiated epithelial cells. Macrophages can be seen in the background (H&E)
Fig 64 - Teratoma –Testicular teratoma, granular background from a cystic lesion was aspirated, together with adipose cells and sheets of epithelial cells (H&E)
Fig 65 - Teratoma – In this smear, from a mature teratoma, epithelial squamous and cylindrical cells can be seen (Giemsa)



  • Representation of the different constituents (epithelial or mesenchymatous)
  • Presence of immature tissues (blastemal, cartilage, etc.)
  • Presence of malignant cells
  • Cystic component



  • Stains correspond to the tissues present


Modern diagnostic techniques

  • Non-contributory


Differential diagnosis

  • With all the tissues and tumours that may be present in mature, immature and/or malignant teratoma


Main points

  • Tumours that arise from a germ cell after first meiotic division