Abstract：
The differential diagnosis for oncocytic renal tumors spans the spectrum from benign entities to more aggressive renal cell carcinomas (RCC). Recent work has characterized a provisional renal oncocytic neoplasm, namely the low-grade oncocytic tumor (LOT), which demonstrates overlapping morphologic features with oncocytoma and chromophobe RCC, but also has a unique immunoprofile (ie, diffusely positive for KRT7, negative for KIT) and a high rate (80% to 100%) of mTOR pathway gene alterations. Given the diagnostic overlap among oncocytic tumors, we looked for concordance between mTOR pathway mutations and LOT. Thirty low-grade renal oncocytic neoplasms underwent histologic review and immunohistochemistry for KRT7 and KIT. Tumors were classified as \"determinate\" (eg, LOT) for tumors with solid, nested or vaguely tubular growth and diffuse KRT7 staining and negative KIT, or \"indeterminate\" if the morphology and/or immunostains did not fully support a definitive LOT diagnosis. Next-generation sequencing was performed without any knowledge of the diagnoses, and identified mTOR pathway mutations in 80% (12/15) of the determinate tumors, compared with 7% (1/15) in the indeterminate group. One determinate tumor was reclassified as papillary RCC (MTOR mutation negative) and 6 indeterminate tumors were confirmed to be oncocytoma (N = 4), clear cell RCC or papillary RCC with reverse polarity, respectively. Overall, integration of morphology, immunohistochemistry, and molecular data enabled a final definitive diagnosis for 70% of tumors (21 of the total 30), with a high concordance (93%) for LOT specifically in the determinate group; the remaining 9 tumors (30%) were classified as renal oncocytic neoplasm, not otherwise specified.
摘要：
嗜酸细胞肾肿瘤的鉴别诊断范围从良性实体到更具侵袭性的肾细胞癌（RCC）。最近的工作描述了一种临时的肾嗜酸细胞肿瘤，即低度嗜酸细胞肿瘤（LOT），这表明与嗜酸细胞瘤和发色细胞RCC重叠的形态学特征，但也具有独特的免疫特征(即，KRT7弥漫性阳性，KIT阴性）和mTOR途径基因改变的发生率很高（80％至100％）。鉴于嗜酸细胞肿瘤的诊断重叠，我们寻找mTOR通路突变与LOT之间的一致性.对30例低级别肾嗜酸细胞肿瘤进行了KRT7和KIT的组织学检查和免疫组织化学检查。肿瘤被归类为“确定性”(例如，LOT）对于实体瘤，嵌套或模糊的肾小管生长和弥漫性KRT7染色和阴性KIT，如果形态学和/或免疫染色不能完全支持明确的LOT诊断，或“不确定”。下一代测序是在没有任何诊断知识的情况下进行的，并在80%（12/15）的决定性肿瘤中鉴定出mTOR通路突变，与不确定组的7%(1/15)相比。1个确定的肿瘤被重新分类为乳头状RCC（MTOR突变阴性），6个不确定的肿瘤被证实为嗜酸细胞瘤（N=4）。具有相反极性的透明细胞RCC或乳头状RCC，分别。总的来说,形态的整合，免疫组织化学，和分子数据使70%的肿瘤（总共30个中的21个）最终得到了明确的诊断，与高一致性（93％）的LOT，特别是在确定组；其余9个肿瘤（30％）被归类为肾嗜酸细胞肿瘤，未指定。
