Stipple sign (transitional cell carcinoma)

The stipple sign refers to the pointillistic end-on appearance on intravenous pyelography or retrograde pyelography of contrast material tracking into the interstices of a papillary lesion. Because the majority of transitional cell carcinomas (TCC) have a papillary configuration, the presence of this sign should raise the suspicion of TCC. While the stipple sign is best seen in large papillary bladder tumors, it can occur anywhere a urothelial tumor expresses papillary architecture.

Be aware, however, that the stipple sign may also be seen with blood clots and fungus balls, and is not pathognomonic for TCC.