American Urological Association - Intratubular Germ Cell Neoplasia (ITGCN)
Intratubular Germ Cell Neoplasia (ITGCN)
- Most germ cell tumors (GCTs) arise from ITGCN.
- Except for spermatocytic seminoma in adults and teratomas and yolk sac tumor in pediatric patients.
- Characterized by proliferation of uncommitted neoplastic germ cells within seminiferous tubules. (Equivalent to "carcinoma in situ" in epithelial malignancies)
- Present in >80% ipsilateral testis and up to 8% contralateral testis to GCT.
- May also be seen in cryptorchid testis.
- Basilar proliferation of atypical large cells with clear cytoplasm with centrally located large nuclei with prominent 1-2 nucleoli. (Resembles seminoma cells)
- Seminiferous tubules may have decreased or absent spermatogenesis, atrophic or has thickened basement membrane.
- Cells may spread in a pagetoid fashion (creeping individually within normal epithelium) to involve the rete testis.
- The tumor cells may fill and distend the tubules (seminoma in situ).
- Immunohistochemistry: placental alkaline phosphatase (PLAP)+, CD117+ and Oct3/4+ (like seminoma).
- Progress to GCT in ~50% of cases within 5 years.