University of California, San Francisco, Department of Pathology, 1825 4th Street, San Francisco, CA, USA.
University of California, San Francisco, Department of Pathology, 1825 4th Street, San Francisco, CA, USA.
Ann Diagn Pathol. 2024 Dec;73:152370. doi: 10.1016/j.anndiagpath.2024.152370. Epub 2024 Aug 19.
Small/flat urothelial lesions are challenging and currently available ancillary immunohistochemistry testing often cannot reliably distinguish between reactive lesions and urothelial carcinoma (UCa). UCa has a characteristic molecular profile, but small/flat urothelial lesions are typically considered too small to perform next generation sequencing (NGS). Herein, we present our institution's experience with utilizing comprehensive DNA-based NGS to evaluate small/flat urothelial lesions (n = 13 cases). NGS was ordered on 7/13 small/flat urothelial lesions initially diagnosed as urothelial atypia, ordered by the pathologist to aid in further diagnosis; the remaining 6/13 cases were diagnosed as urothelial carcinoma in situ (uCIS), ordered by a treating oncologist. The test was considered as adding value if it yielded pathogenic or likely pathogenic alterations previously associated with urothelial carcinoma in the literature. Macroscopic dissection was determined necessary in all cases and obtained either by scraping (7), punch biopsy (5) or scooping (1) of paraffin tissue blocks. In 4/13 cases, tumor content was considered low (<25%); in 2/13 cases, DNA quantity yield was considered below optimal (<250 ng); all cases met required DNA quantity for testing (>50 ng). Mean target coverage ranged: 498 to 985 (optimal >500 reads). NGS testing identified mutations compatible with urothelial carcinoma in all 7 cases initially diagnosed as atypical; and in one case, the tumor recurred as a lung metastasis. All 6 uCIS had NGS testing results concordant with UCa. In conclusion, despite small sample quantity with low tumor content and DNA concentration yield, NGS testing with appropriate methodology can be considered in the setting of small/flat urothelial lesions to aid in diagnosis or per oncologist request and yield interpretable results.
小/扁平的尿路上皮病变具有挑战性，目前可用的辅助免疫组织化学检测通常无法可靠地区分反应性病变和尿路上皮癌（UCa）。UCa 具有特征性的分子谱，但小/扁平的尿路上皮病变通常被认为太小而无法进行下一代测序（NGS）。在此，我们介绍了我们机构利用综合 DNA 基 NGS 评估小/扁平尿路上皮病变（n=13 例）的经验。7/13 例最初诊断为尿路上皮不典型的小/扁平尿路上皮病变由病理学家下订单进行 NGS，以协助进一步诊断；其余 6/13 例被诊断为原位尿路上皮癌（uCIS），由治疗肿瘤学家下订单。如果该检测产生了以前在文献中与尿路上皮癌相关的致病性或可能致病性改变，则认为该检测具有附加值。所有病例均需进行宏观解剖，通过刮除（7 例）、穿刺活检（5 例）或刮匙（1 例）获取石蜡组织块。在 4/13 例中，肿瘤含量被认为较低（<25%）；在 2/13 例中，DNA 量产量被认为不理想（<250ng）；所有病例均符合检测所需的 DNA 量（>50ng）。平均目标覆盖范围：498 至 985（理想值>500 个读数）。NGS 检测在所有 7 例最初诊断为非典型的病例中均发现与尿路上皮癌相符的突变；并且在 1 例中，肿瘤复发为肺转移。所有 6 例 uCIS 的 NGS 检测结果与 UCa 一致。总之，尽管样本量小，肿瘤含量和 DNA 浓度低，但在小/扁平的尿路上皮病变的情况下，结合适当的方法，NGS 检测可以考虑用于辅助诊断或根据肿瘤学家的要求进行，并产生可解释的结果。
