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

Atypical squamous cells in urine cytology are associated with a significant risk of high-grade malignancy

BACKGROUND

Atypical squamous cells (ASC) in urine cytology are rarely found, and their clinical significance is not well studied. Previous studies were limited by a small number of cases and a lack of objective grading of ASC and/or their correlation with accompanying urothelial cell abnormality (UCA).

METHODS

The institutional database was searched over 10 years for urine cytology reports containing ASC or from patients who had a concurrent diagnoses of high-grade (HG) urothelial carcinoma with squamous differentiation or squamous carcinoma. ASC were defined as keratinized squamous cells and were subcategorized as reactive, koilocytosis, low-grade (LG) atypia, and HG atypia. Correlations with age, sex, specimen type, accompanying UCA, number of ASC, and the risk of HG malignancy (ROHM) were assessed.

RESULTS

ASC were present in 0.15% of all urine specimens (123 of 81,018). Slides and clinical follow-up were available on 91 patients (median age, 71 years). LG and HG squamous atypia had ROHMs of 70% and 92%, respectively. ASC not accompanied and accompanied by UCA had ROHMs of 37% and 94%, respectively. Most malignancies (34 of 67; 51%) showed rare ASC in urine. Reactive changes and koilocytosis had 0% ROHM.

CONCLUSIONS

ASC in urine cytology is a significant finding and is associated with a high ROHM. In the absence of accompanying UCA, LG squamous atypia had a lower ROHM than HG atypia. In the presence of UCA, LG and HG squamous atypia had ROHMs of over 90%. These findings suggest that ASC and their grade of atypia should be noted in the cytology report, and clinicians should be made aware of their clinical significance.

Condyloma acuminatum of the urinary tract demonstrates atypical squamous cells in urine cytology

Urine cytology of urinary tract condylomas has not been systematically studied. We analyzed cytologic features of urinary tract condylomas and evaluated potential diagnostic challenges and pitfalls. We retrospectively reviewed urine cytology of urinary tract condylomas from 2 academic institutions (2015-2022). Among 20 patients with urinary tract condylomas, 6 had urine cytology (2 samples in 1 patient), including 3 men and 3 women (mean age, 74.3 years; range, 65-86 years). Original interpretations were negative for high-grade urothelial carcinoma (NHGUC; n = 4), atypical urothelial cells (n = 1), reactive urothelial cells (n = 1), and negative for malignancy (n = 1). Squamous cells were noted in 3 cases, atypical squamous cells (ASC) consistent with low-grade squamous intraepithelial lesion (LSIL) were noted in 1 case, and in 3 cases, the presence of squamous cells was not mentioned. All urines were reclassified according to The Paris System as NHGUC. Specimens were composed of benign urothelial cells and groups or isolated ASC consistent with LSIL (n = 4), atypical keratinized squamous cells (n = 2), and ASC that did not meet LSIL criteria (n = 1). The LSIL cells showed nuclear enlargement (n = 4), hyperchromasia (n = 4), perinuclear halo (n = 3), nuclear membrane irregularity (n = 4), orangeophilic cytoplasm (n = 3), and binucleation (n = 4). The atypical keratinized squamous cells showed hyperchromasia (n = 2), nuclear membrane irregularity (n = 2), keratin pearls (n = 2), and binucleation (n = 1). The ASC that did not meet LSIL criteria showed nuclear enlargement and orangeophilic cytoplasm. Many urinary tract condylomas (57%) demonstrate classic LSIL features in urine cytology. Less frequent cases can mimic keratinizing squamous cell carcinoma (28%) or demonstrate ASC not diagnostic of LSIL (15%).

Koilocytes due to HPV in the urine sediment

Koilocytes are the hallmark of human papillomavirus (HPV) infection and can be observed during routine cytology tests stained by Papanicolaou. However, the test is not part of the routine urinalysis report. Here we describe a case on HPV subtype 6 infection diagnosed after finding koilocytes in fresh and unstained urine sediment of a kidney allograft recipient male patient.