Tumor composed of a mixture of germ cell and sex-cord-stromal elements.

Synopsis :

• one third detected before the age of 15
• frequent association with abnormalities in the secondary sex organs, with detection of a Y chromosome in over 90% of cases
• bilateral in at least 38% of cases
• usually develops in a phenotypic female, frequently virilized (see also gonadal dysgenesis)
• may be overgrown by dysgerminoma or by other neoplastic germ cell elements

Histology :

• germ cells, similar to those of dysgerminoma or seminoma
• sex cord derivatives resembling immature sertoli or granulosa cells
• stromal derivatives mimicking luteinized or Leydig cells devoid of Reinke crystals mnay be present

• solid nests of inimately admixed germs cells and sex cord derivatives, the latter arranged in 3 typical patterns :
  • coronal pattern at the periphery of the nests
  • surrounding individual or collections of germ cells
  • surrounding speces containing an eosinophilic PAS-positive material, resembling Call-Exner bodies

• additional processes :
  • hyalinization
  • calcification, originating in the Call-Exner-like bodies
  • overgrowth by a malignant germ cell component, usually dysgerminoma (50% of cases) or another malignant germ cell element (in an additional 10%)

• if the nature of the gonad is identified it is either a streak or a testis (contralateral gonad : idem)

Associations

 30% of patients with mixed gonadal dysgenesis
 less than 3% of patients with true hermaphrodism
 50% of patients with 46XY pure gonadal dysgenesis
 very high frequency of associated malignant germ cell tumor
 dysgerminoma (malignant germ cell tumor most commonly associated with gonadoblastoma)

See also

 gonadal tumors
 intersex disorders