Intratubular germ cell neoplasia in testicular teratomas and epidermoid cysts. Correlation with prognosis and possible biologic significance.

The clinicopathologic features of 4 testicular teratomas in infants, 13 testicular epidermoid cysts in adults, and 8 pure teratomas in adults were compared. Intratubular germ cell neoplasia (ITGCN, carcinoma in situ) was observed in 88% of the teratomas in adults; 63% of the patients in this group had metastases and 37% died. No ITGCN was observed in infant testes with teratomas or adult testes with epidermoid cysts; all of the neoplasms in the latter two groups behaved as benign tumors. ITGCN is associated with malignant potential (P = 0.0004; Fisher's exact test). These tumors comprise a spectrum of clinicopathologic entities that probably reflect differences in pathogenesis.