Intracranial germ cell tumour (embryonal carcinoma with teratoma) with complex karyotype including isochromosome 12p.

We report the chromosomal characteristics of a malignant teratoma with embryonal carcinoma component located in the pineal region of a 15-year-old boy. Chromosome analysis showed a near-triploid complex karyotype (62 chromosomes), including two copies of an isochromosome 12p, confirmed by fluorescence in situ hybridization analysis. The present findings indicate that isochromosome 12p formation is probably associated with the development of malignant germ cell tumours.