Chromophobe variant of RCC is associated with
|A||Trisomy 7 and trisomy 17|
|B||Loss of chromosome|
|C||Gain of 5|
|D||VHL gene mutation|
a. Renal cell carcinoma has 5 histological subtypes as follows: clear cell (MOST COMMON), chromophillic (15%) , chromophobe(5%), Oncocytoma(3%), and collecting duct(2%)
b. Unusually clear cell with a cytoplasm rich in lipids and glycogen characterize clear cell carcinoma, which is most likely to show 3p deletion.
c. Chromophiic tumors tend to be bilateral and multifocal and may have trisomy 7 and trsomy 17
d. Large polygonal cells with pale reticular cytoplasm characterize chromophobe carcinoma , which does not exhibit 3p deletion, show multiple loss of entire chromosome i.e 1, 2, 6, 10,13,17, 21 leading to a low chromosome number.
e. It resembles the intercalated cells type B from the cortical collecting duct. The antigenic profile of this type of carcinoma exhibit collecting duct pleomorphic features.
f. No male preponderance is found.
g. It consist of one or more solid tumor nodule with a slightly lobulated surface and the cut surface appear orange.
h. It is diagnosed by a positive Halo”s acid iron colloid stain and is positive for carbonic anhydrase C , but doesn’t exhibit band 3 protein.
i. Renal oncocytoma consist predomiantly of eosinphilic cells , in a characteristic nested or organoid pattern , that rarely metastasize and donot exhibit 3p deletion or trisomy 7 or 17
j. In Von hippen landau disease there is a deletion of 3p. Mutation of VHL gene result in accumulation of hypoxia inducible factors that stimulate angiogenesis through vascular endothelial growth factor and its receptors.