楼上说的有道理，但是拿去浙一医院会诊的时候，王丽君老师就是凭上面几张HE直接诊断：囊性肾细胞癌！

崇拜啊！王老师！

后来病人做了肾脏切除根治手术！续传肾脏下来的图。

传上本例希望大家以后碰到肾脏的囊肿要慎重一点！尤其是囊壁似有内衬泡沫样细胞的时候。

单凭这些细胞不敢诊断多房囊性肾细胞癌，必须做免疫组化。

Sorry.  I cannot type in Chinese. I hope you can understand it.

This is multilocular cystic renal cell carcinoma.

Morphologically you can see the cysts lined by clear cels. There are clear cells forming nest in the stroma or septa. Normally the clear cells have small dark nuclei.

In kidney the differentials of cystic lesions mainly include cystic nephroma,  mixed epithelial and stromal tumor (MEST), simple cyst, atypical renal cyst, renal cell carcinoma with cyst (cystic, necrotic RCC or multilocular cystic RCC), polycystic kidney disease.

Basically cystic nephroma and MEST are the same kind of benign tumor. They predominantly occur in female patient. The epithelial lining is benign and stroma cells are spindle, similar to the ovarian stromal cells. The stromal cells are positive for estrogen receptor and progesterone receptor. They can be misdiagnosed on core biopsy since the epithelial cells may have reactive or degenerative atypica. The best clue is the blue spindle stromal cells under the epithelial area.

Atypical renal cysts have clear cell lining. There is not papillary projection or nest of clear cells in the septa. You need to inform the urologist that the patient should be followed closely.

Multilocular cystic RCC: like current case. There are nests of clear cells and papillary projection. For diagnosing cystic RCC you will not see large solid area of clear cells. Generally cystic RCC has excellent prognosis. In some case there are small nest RCC cells you can call multicystic RCC low malignant potential.

Cystic, necrotic RCC:   often has papillary structure or solid clear cells. There are florid necrosis and cyst formation.