Next-generation sequencing has diagnostic utility in challenging small/flat urothelial lesions

Area of Science:

• Urology
• Oncology
• Molecular Pathology

Background:

• Distinguishing small/flat urothelial lesions is clinically challenging.
• Current immunohistochemistry methods often lack reliability for differentiating reactive lesions from urothelial carcinoma (UCa).
• Urothelial carcinoma has a distinct molecular profile, but small samples preclude traditional next-generation sequencing (NGS).

Purpose of the Study:

• To evaluate the utility of comprehensive DNA-based NGS for small/flat urothelial lesions.
• To assess NGS performance in cases with limited tumor content and DNA yield.
• To determine if NGS can aid in the diagnosis of challenging urothelial lesions.

Main Methods:

• Utilized DNA-based NGS on 13 small/flat urothelial lesions.
• Samples included lesions initially diagnosed as urothelial atypia or urothelial carcinoma in situ (uCIS).
• Macroscopic dissection (scraping, punch biopsy, scooping) was employed; DNA quantity and target coverage were assessed.

Main Results:

• NGS identified urothelial carcinoma-compatible mutations in all 7 atypical lesions.
• NGS results were concordant with UCa in all 6 uCIS cases.
• Interpretable results were obtained despite low tumor content and DNA yield in some cases.

Conclusions:

• Comprehensive DNA-based NGS is a valuable tool for diagnosing small/flat urothelial lesions.
• NGS can provide interpretable results even with limited sample quantity and low DNA yield.
• This molecular approach aids in differentiating benign from malignant urothelial conditions, supporting clinical decision-making.