Cytogenetics of primary testicular nonseminoma, residual mature teratoma, and growing teratoma lesion in individual patients.

Residual mature teratoma (RMT) is often left behind when metastases of primary nonseminomatous germ cell tumors (NSs) are treated with chemotherapy. RMT is composed of fully differentiated somatic tissue. A growing teratoma (GTE) lesion may occur after (incomplete) resection of RMT. To shed light on tumor progression or the mechanism(s) of therapy related differentiation we investigated the chromosomal pattern of the primary NSs and RMTs in twelve patients, of the primary NS, RMT, and GTE lesion in one patient, and of the RMT and GTE lesion in two patients. Although several chromosomal differences are observed between the RMT and NSs and between the GTE and RMTs in the same patient, we obtained no evidence that specific chromosomal alteration(s) play a role in metastasis or differentiation.