Cerebrospinal fluid and metastasis of transitional cell carcinoma of the bladder.

Two cases are presented of cerebrospinal fluid with tumor cells metastatic from transitional cell carcinomas of the bladder. They demonstrate that in spite of the rarity of transitional cell carcinoma's metastasizing to the central nervous system (0.4% to 0.6%), it is necessary to consider the bladder as the primary site and to obtain urinary cytology in such cases when the primary tumor is still unknown.