Kidney

Renal Cell Carcinoma
The use of IHC in the setting of renal cell carcinoma (RCC) usually falls into one of two categories: (1) carcinoma of unknown primary, or (2) differentiation of RCC subtypes.  Dependent upon which category one is in dictates what type of panel to utilize.
 
RCC vs. Other Malignancy
>80% expression in RCC
>80% expression in RCC
CK7/CK20
Both typically negative in clear cell RCC
>95% expressión in convencional clear cell RCC
>85% expression in clear cell and papillary subtypes
Variable but usually positive (author’s experience)
Positive
RCC Conventional Clear Cell type is one of a limited differential with co-expression of vimentin and cytokeratin.
RCC Subtype Differentiation
IHC may be helpful in sub-typing a RCC tumor.  This usually occurs in the setting of differentiating between a chromophobe RCC and a conventional clear cell RCC with eosinophilic cytoplasm.  The best way to confirm a clear cell RCC is to take more sections, and definitively identify clear cell areas.  Unfortunately, on small biopsies this may not be possible, and IHC provides helpful clues.
 
Negative in chromophobe RCC/oncocytoma, and >85%+ in clear cell RCC.
Usually expressed in most RCCs, but literature varies widely.  CAM5.2 probably better consistency and sensitivity.
>80% + in chromophobe RCC/oncocytoma, and negative (<5%+) in clear cell RCC.
Oncocytomas are usually negative for CK7, while chromophobe RCC is often positive.
Almost all oncocytomas and chromophobe RCCs show expression of E-Cadherin.  Clear cell and papillary RCCs are typically negative.  Xp11.2 translocation RCC are usually positive.
TFE3 is a specific marker for Xp11.2 translocation renal cell carcinomas, and is expressed in >90% of such cases.
 
As a general rule of practice in IHC, it is best to have both positive and negative markers for differentiation. 
 
IHC Stain
RCC
Clear Cell
RCC
Papillary
RCC
Chomophobe
RCC
Xp11.2
94-100%
67-93%
+/- 0-72%
+ >90%
0-37%
80-87%
73-86%
17%
=
=
=
N/A
35% (varies)
82%
16%
11%
87%
100%
=
66%
92%
87%
+/- 0-82%
 
98%
87%
83%
 
72-85%
87-95%
0-91%
 
0-5%
0-13%
82-100%
 
88%
>90%
>90%
 
Negative
Negative
Positive
68%
 
AE1/AE3 has varying positivity in the literature.  Part of this is probably due to that AE1/AE3 lacks CK18, which is expressed by most RCCs.  Other CKs have varying expression.  CAM5.2 is recommended over AE1/AE3.
Differential Diagnosis
Adrenocortical Carcinoma: AE1/AE3 -, EMA -, RCC Ma., Inhibit +, Calretinin +
 
Angiomyolipoma:  MART-1 +, HMB-45 +, Tyrosinase +, Smooth Muscle Markers +, Cytokeratins -, EMA –
Photomicrographs
Chomophobe Renal Cell Carcinoma
Chromophobe renal cell carcinoma with perinuclear halos, oncocytic features, and scattered vegtable-like cells.
Chromophobe Renal Cell Carcinoma
Chromophobe renal cell carcinoma with perinuclear halos, oncocytic features, and scattered vegtable-like cells.
Chomophobe Renal Cell Carcinoma - E-Cadherin
E-Cadherin expression in a chromophobe RCC.
Chromophobe Renal Cell Carcinoma - CD117
CD117 expression in a chromophobe RCC.

References
 Arch Path Lab Med – Vol. 135, Jan. 2011 (Truong & Shen).
 
Pan, CC. “Differential Immunoprofiles of Hepatocellular Carcinoma, Renal Cell Carcinoma, and Adrenalcortical Carcinoma.” Appl Immunohistochem Mol Morphol. Vol. 13, No. 4, Dec. 2005.
 
Diagnostic Immunohistochemistry: Theranostic and Genomic Applications. [edited by] DJ Dabbs. 3rd Edition.  Elsevier, 2010.
 
Shen, SS. “Role of Immunohistochemistry in Diagnosing Renal Neoplams: When Is It Really Useful?”Arch Pathol Lab Med, Vol. 136, April 2012.  pp. 410-417. 
 
Camparo, P., Vasiliu, V., Molinie, V., Couturier, J., Dykema, K. J., Petillo, D., et al. (2008). Renal translocation carcinomas: clinicopathologic, immunohistochemical, and gene expression profiling analysis of 31 cases with a review of the literature. The American Journal of Surgical Pathology, 32(5), 656–670. doi:10.1097/PAS.0b013e3181609914