Case Series of Thermal Cautery Artifact in Urine Cytology: An Uncommon Finding but a Potential Pitfall.

Abstract

Therapeutic modalities used in bladder lesions/neoplasms (electrocautery, fulguration, and laser) could produce morphologic alterations leading to diagnostic challenges. While often seen on histology, they can present in urine cytology as atypia or even raise the concern for malignancy. Herein, we present clinicopathologic findings of four patients with cautery artifact in urine cytology. The authors' lists and a computerized search of urine cytology with features of thermal cautery artifact were collated. Slides and clinicopathologic variables (prior specimens, concurrent and follow-up surgical specimens, age, sex, manner of urine collection, cystoscopy, and treatment procedure during cystoscopy) were reviewed. Four cases were identified. Procedures performed during cystoscopy included laser therapy (n = 2), postbiopsy cauterization (n = 1), and fulguration (n = 1). All cases showed spindled cells with delicate bipolar cytoplasm, "cigar-shaped" nuclei, smooth to slightly irregular nuclear membranes, and arranged singly and loosely cohesive to lamellar stacks. Few atypical well-preserved, undistorted cells were identified in 2/4. The concurrent biopsies showed superficial cellular fragments with thermal artifact (n = 1) and rare atypical cells (n = 2). Follow-up biopsies in two cases had high-grade urothelial carcinoma both of which were diagnosed as atypical urothelial cells on cytology. Thermal cautery artifact in urine cytology is rare and can be seen following laser, electrocautery, and fulguration. The spindling artifact can render some degree of difficulty in assessing for the presence of urothelial atypia both in cytology and biopsy. Familiarity with these cytologic features, knowledge of the treatment procedure, attention to the cytologic findings of well-preserved cells and repeat sampling in cases with atypical urothelial cells in patients with history of malignancy is essential.