电镜 may be helpful if we want to differentiate oncocytoma from chromophobe RCC (eosinophilic variant). The oncocytoma has abundant mitochondria. The chromophobe RCC has numerous vesicles in cytoplasm. 电镜 has littel value to differentiate RCC from TCC when immunostains are readily available in nowadays.

The information (肾盂没有异常) you provided above is more important than electron microscopy. It is important because "virtually all transitional cell carcinoma of the renal pelvis and ureter are associated  with changes ranging from hyperplasia to carcinoma in situ in the mucosa elsewhere in the specimen" (quoted from Fletcher's "Diagnostic Histopathology of Tumors").

 谢谢各位老师！

本例最具有特点的是血管轴乳头结构，有尿路上皮样分化和肾小球样结构。

可否称为 papillary  renal cell carcinoma with urothelial differentiation ?

• Thanks to Dr. Chiang for such a fascinating and challenging case. 
• The idea of "papillary  renal cell carcinoma with urothelial differentiation" is very novel one. I certainly have never seen or thought about such a concept. A tumor with mixed RCC (renal tubular differentiation) and urothelial differentiation probably will be very difficult to prove. 
• To call this tumor a RCC for sure, we might need to run some renal tissue specific markers such as RCC marker, Pax2, Pax8 and may be P504.  Unfortunately we do not have good tissue markers for urothelial carcinoma (uroplakin-3, throbomodulin).
• But I would argue that tumor with "肾小球样结构"does not mean renal differentiation. It is just a description of morphology; we can see it in other GU tumors such as prostate carcinoma, yolk sac tumor metanephric adenoma and low grade type 1 papillary RCC.

 很抱歉，英文“papillary  renal cell carcinoma with urothelial differentiation”表达有误，应该是papillary  renal cell carcinoma with urothelial-like differentiation ，涵义是形态学有些类似尿路上皮癌样，乳头有多层细胞，包括免疫标记也有重叠。

我们是基层医院见的东西少，总感觉这个例子的图像很特别，感谢steveshen等老师对本例的评价及关注，我会继续做些工作。谢谢！ 

 个人愚见：

本例病例无论从组织，细胞，以及免疫染色形态学上来说都具备某些较为特殊的表现。

乳头状结构（纤维血管间质，仔细观察尿路上皮的乳头间质，可以发现平行于基底膜有排列的薄壁血管，因此仅从纤维血管间质区分RCC与TCC是有欠妥当）。肾小球样排列结构（正如沈老师所说，许多尿路上皮肿瘤以及肾脏起源肿瘤甚至前列腺的肿瘤也可具有此种排列结构，正如血管外皮瘤样排列也可以是多种肿瘤的组织学排列而非血管源性所特有，因此仅从肾小球样结构来推测RCC显然欠缺说服力）。细胞学特征，围绕血管周围排列着两种胞浆着色截然不同的细胞，暂且称呼为内外带细胞，内带细胞1-2层，圆形，胞浆透亮，包膜清晰；外带细胞圆至略带梭形，胞浆嗜酸性，多层排列。免疫组化染色，Vim染色血管及内带细胞明显着色而外带细胞阴性，角蛋白染色刚好相反。至于RCC对鉴别TCC与RCC的免疫表达意义有待商榷。而P63的着色结果令人怀疑。个人认为Vim的颇具特征性的着色，对反应肿瘤的本质可能具备某些重要的意义。大家的讨论都在于鉴别RCC与TCC，肾盂黏膜取材未见显著的异常貌似排除TCC的有力证据，但根据WHO的TCC的遗传学相关研究来看，绝大多数的浸润性尿路上皮癌或多或少都存在残存黏膜的不典型增生或者原位癌的表现，但却有少部分的尿路上皮癌并无此证据的存在，即初始就发展为浸润癌，特别是老年患者。在此，我有一种想法，即这些围绕血管周排列的包膜清晰，胞浆透亮的细胞，是否是一些被称为血管周细胞抑或是周皮细胞的增生？？如果能够加做这方面的抗体标记物，是否会有一些意想不到的结果呢？这些亮细胞Vim是阳性的，但显然不够；对外带的细胞截然不同的染色结果来看，或许是同一种细胞两种不同的分化方向，抑或是两种截然不同的细胞起源。

就有限的图片显示的组织学结构来看，若然排除上面本人的设想，就一个85岁的患者来说，综上所述，针对TCC与RCC,个人更倾向于TCC的诊断。