WKY/Ztm-ter: a new rat inbred strain on the WKY/Ztm genetic background with congenital teratomas.

We describe a new rat model for teratomas (WKY/Ztm-ter) which arose through a spontaneous mutation in the inbred WKY/Ztm rat strain. When the tumours of the gonads became clinically apparent, affected males were 14 to 224 days of age, whereas the females only developed tumours between days 21 and 63. Tumour incidence is not gender-dependent. However, almost all females develop bilateral tumours, while 50% of the males show unilateral tumours. Histologically, all examined tumours (n = 65) represent partially undifferentiated teratocarcinomas.