SPINDLING ARTIFACT OF UROTHELIAL CELLS IN POST-LASER TREATMENT URINARY CYTOLOGY

We reviewed 22 post-laser (Nd:YAG laser) coagulation bladder washes co llected immediately after treatment. All washes demonstrated a strikin g artifact of cellular spindling. These spindled cells occurred singly , in loose clusters, and in lamellar stacks and had elongated nuclei w ith dense chromatin and bipolar cytoplasm that was fused in the stacks . Concurrent biopsies demonstrated similar cytologic changes. The spin dling is a nonspecific epithelial response to heat. Conventionally ele ctrocauterized epithelia show this artifact in biopsies, but since onl y the base of the lesion and surrounding urothelium are subjected to h eat with electrocautery, the relatively few spindled epithelial cells created presumably go undetected in cytology specimens. With laser tre atment, however, the whole urothelial surface of the lesion is coagula ted, producing a much greater number of spindled cells. It is importan t to avoid misinterpreting the spindled cells as cells from a mesenchy mal neoplasm or a sarcomatoid carcinoma, mistakes that were made in so me of our initial cases. Malignancy cannot be evaluated when cells exh ibit spindling artifact, this judgement should be made on undistorted cells. Thus, pre-laser and post-laser washes should be submitted for e valuation of malignancy.