American Urological Association - Gonadoblastoma
- Combination of GCT and SCT.
- Mixture of seminoma-like germ cells and immature SCT elements that resemble Sertoli cell tumor or granulosa cell tumor.
- Extremely rare, usually encountered in patients with dysgenetic gonad.
- Most patients are phenotypically female (80%); majority has Y chromosome.
- During embryonic development, immature bi-potential gonads fail to differentiate along male pathway.
- 30% has bilateral testicular involvement.
- Gross: solid yellow-tan nodules with gritty calcifications.
- Well-rounded nests of large pale seminoma-like cells with abundant clear cytoplasm and well-defined cytoplasmic membranes (image A) & (image B).
- Admixed are dark angular sex-cord cells that tend to palisade at the periphery of the tumor nests (looks like Call-Exner bodies).
- Basement membranes can become very hyalinized and even calcified.
- Less often, nodular aggregates of Leydig cells are seen as well.
- Immunohistochemistry: Germ cells: PLAP+, CD117+, Oct3/4+ and stromal cells: inhibin+ or calretinin+.
- Represent pre-malignant lesions from which malignant GCTs can arise; therefore, since majority of patients have gonadal dysgenesis and therefore run a high risk of bilateral tumors, the recommended treatment is bilateral orchiectomy.