Cytogenetic findings in a metastasizing primary testicular chondrosarcoma.

The first case of a primary chondrosarcoma of the testis is reported. The testicular tumor, 2.5 cm in diameter, metastasized to the retroperitoneal lymph nodes in a 24-year-old male. Histologically, the testicular tumor and the lymph node metastases revealed a well-differentiated chondrosarcoma. Cytogenetic analysis of the retroperitoneal metastases showed a complex chromosomal aberration with two copies of the isochromosome of the short arm of chromosome 12. This is a specific chromosomal anomaly in testicular germ cell tumors. Thus, the cytogenetic analysis proved the germ cell origin of tumor cells as opposed to a possible paratesticular mesenchymal histogenesis. Moreover, the triploid modal chromosomal number of tumor cells confirmed the relationship between polyploidization and a high degree of differentiation in germ cell tumors. These findings stress the clinical relevance of the cytogenetic analysis in at least a subset of cytogenetically well-characterized solid tumors.