Significance of cytologic detection of low-grade squamous intraepithelial lesion in urine

Cellular changes of low-grade squamous intraepithelial lesion (LSIL) are uncommon in urine cytology. There is limited data regarding the clinical aspects and follow-up of patients with such findings. The aim of this study is to examine the clinicopathologic correlates of LSIL in urine cytology.

A database search was conducted for urine cytology samples from January 1, 2000 to March 31, 2013 for the keywords "HPV," "LSIL," "koilocytes," and "atypical squamous cells genital tract." Thin Prep preparations (Hologic, Marlborough, MA) on the retrieved cases were reviewed. Cases with morphologically unequivocal LSIL were further analyzed.

Twenty-five cases-20 women (ages 17-65 years), 5 men (ages 70-84 years)-of voided urine cytology fulfilled the study criteria. History of genital tract squamous dysplasia and/or carcinoma was present in 10 patients (50%). Eight patients (30%) were immunosuppressed. Eleven patients had LSIL or atypical squamous cells on cytologic follow-up. One patient developed penile squamous cell carcinoma and another patient developed vulvar intraepithelial neoplasia 3, 5 years and 3 years from the index urine cytology, respectively. Ten women had human papillomavirus testing (Hybrid Capture 2; Digene Corporation, Gaithersburg, MD), of which 8 were positive (within 6 months to 4 years from the index urine cytology).

Our study reveals that LSIL is an uncommon finding in urine cytology, and in most cases, it is associated with LSIL in the genital tract. However, occasionally, it may lead to the detection of high-grade squamous intraepithelial lesions or human papillomavirus-associated squamous cell carcinomas of the genital tract.