Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania.
Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania.
J Am Soc Cytopathol. 2021 Mar-Apr;10(2):216-224. doi: 10.1016/j.jasc.2020.09.012. Epub 2020 Sep 30.
Fine-needle aspiration (FNA) of nodal metastases plays a key role in the diagnosis of oropharyngeal squamous cell carcinoma (OPSCC). Because of significant clinical implications of human papillomavirus (HPV)-related OPSCC, immunohistochemistry for p16 as a surrogate marker for high-risk HPV is an important ancillary test. After our laboratory switched from CytoLyt to formalin fixative for FNA needle rinses generating cell block (CB) material, we investigated the impact of this protocol change on the accuracy of p16 results.
FNA specimens of head and neck lesions with p16 staining performed on CB, from 1 year before and after the implementation of formalin-fixed CB (FCB) were identified. Nuclear and cytoplasmic p16 expression was scored and compared to p16 status on corresponding surgical specimens.
There were no false-positive results with either fixative. CytoLyt-fixed CB (CCB) had 47% (7 of 15) false-negative cases, whereas FCB had none, with 100% diagnostic accuracy for p16-negative (n = 6) and p16-positive (n = 15) results. False-negative CCB showed 0% to 10% nuclear and 0% to 65% weak cytoplasmic staining, whereas true-positive CCB showed 10% to 85% nuclear and 35% to 90% cytoplasmic staining. p16-negative FCB showed 0% nuclear and cytoplasmic staining, and p16-positive FCB showed 30% to 100% moderate-strong nuclear and cytoplasmic staining. Interobserver variability was greater with CCB.
In our laboratory, formalin fixation of CB material improved the accuracy of p16 interpretation. Staining in FCB was also more robust than CCB, which showed weaker cytoplasmic and more focal nuclear staining. Therefore, we advocate formalin fixation for head and neck cytology specimens that may require p16 testing.
细针穿刺（FNA）对淋巴结转移的诊断在口咽鳞状细胞癌（OPSCC）的诊断中起着关键作用。由于人乳头瘤病毒（HPV）相关 OPSCC 具有重要的临床意义，p16 免疫组化作为高危 HPV 的替代标志物是一项重要的辅助检测。在我们的实验室将 FNA 针冲洗产生细胞块（CB）的材料从 CytoLyt 更换为福尔马林固定剂后，我们研究了该方案改变对 p16 结果准确性的影响。
鉴定了在实施福尔马林固定 CB（FCB）之前和之后的 1 年内进行 CB 上的头颈部病变的 FNA 标本，这些标本均进行了 p16 染色。核和细胞质 p16 表达进行了评分，并与相应手术标本的 p16 状态进行了比较。
两种固定剂均无假阳性结果。CytoLyt 固定 CB（CCB）有 47%（7/15）假阴性病例，而 FCB 则没有，p16 阴性（n=6）和 p16 阳性（n=15）结果的诊断准确率为 100%。假阴性 CCB 显示 0%至 10%核和 0%至 65%弱细胞质染色，而真阳性 CCB 显示 10%至 85%核和 35%至 90%细胞质染色。p16 阴性 FCB 显示 0%核和细胞质染色，而 p16 阳性 FCB 显示 30%至 100%中度强核和细胞质染色。CCB 的观察者间变异性更大。
在我们的实验室中，CB 材料的福尔马林固定提高了 p16 解读的准确性。FCB 的染色也比 CCB 更稳健，后者显示出较弱的细胞质和更集中的核染色。因此，我们提倡对头颈细胞学标本进行福尔马林固定，这些标本可能需要进行 p16 检测。
