<prompt> Stipple sign in transitional cell carcinoma of the renal collecting system is best demonstrated byIntravenous urographyRetrograde pyeloureterographyRadionuclide scanUltrasound scan  <response>: The stipple sign refers to tracking of contrast into the interstices of a papillary lesion. This is seen in Intravenous urography intravenous pyelography of transitional cell carcinoma of renal collecting sysym. Other signs on IVP are filling defect; Calyceal obliteration amputation; hydronephrosis with soap bubble nephrogram. 