Trisomy 3 as the sole karyotypic change in a pediatric immature teratoma.

Cytogenetic analysis of short-term cultured cells from an immature ovarian teratoma of a 9-year-old girl disclosed an extra copy of chromosome 3 as the sole clonal abnormality. The fact that trisomy 3 was previously reported as the only karyotypic change in two ovarian germ-cell tumors--one teratoma NOS and one immature teratoma--suggests that gain of chromosome 3 constitutes an early and pathogenetically important change in a subset of female germ-cell tumors.