Colloidal Iron Staining in Renal Epithelial Neoplasms, Including Chromophobe Renal Cell Carcinoma

Abstract

Positive staining with Hale's colloidal iron stain, or modifications thereof, is considered a diagnostic feature for chromophobe renal cell carcinoma and has been used as a discriminatory feature to differentiate it from other renal tumors. We studied colloidal iron staining in 62 cases encompassing a wide histologic spectrum of renal neoplasms (14 chromophobe renal cell carcinomas, 19 renal oncocytomas, 11 each of granular variants and conventional clear cell renal cell carcinomas, and 7 eosinophilic variants of papillary renal cell carcinoma) to investigate the specificity of the stain for chromophobe renal cell carcinoma. In cases of chromophobe renal cell carcinoma, sections from two different areas were stained to ascertain whether there was any spatial variation in staining. Influence of staining techniques on the results also was investigated by staining each case of chromophobe renal cell carcinoma using two different methods: the traditional Hale's and a modified Mowry's technique, which treats sections with 3% acetic acid before adding the colloidal iron. Our results show that positive staining with colloidal iron stain is not limited to chromophobe renal cell carcinoma, however, a diffuse and strong, reticular staining pattern was observed only in cases of chromophobe renal cell carcinoma (14 of 14). The staining patterns were less consistent in all other renal neoplasms and differed from the reaction observed in chromophobe renal cell carcinoma. Most renal oncocytomas (16 of 19) had focal and weak, fine dustlike positivity, and all clear cell carcinomas showed focal, coarse, dropletlike positive staining (22 of 22), in addition to a focal, coarse, bubbly pattern in 5 of 11 clear cell subtypes. Although all seven cases of the eosinophilic variant of papillary renal cell carcinoma showed strong, coarse, dropletlike staining, most of the positivity was coincident with the Perl's (prussian blue) reaction, indicating that the staining was due to hemosiderin, which is frequently present in this histologic subtype of renal cell carcinoma. Staining intensity did not vary considerably among different areas of chromophobe renal cell carcinoma, but the modified Mowry's method yielded brighter and sharper reticular staining, as compared with the Hale's method. Our results show that in the appropriate morphologic context diffuse and strong reticular positivity using the modified Mowry's colloidal iron stain method is highly characteristic for chromophobe renal cell carcinoma. Treatment of sections with 3% acetic acid before adding the colloidal iron gives technically superior staining results.

Parvalbumin Is Constantly Expressed in Chromophobe Renal Carcinoma

“…For all tumors, serial 5-m sections were stained with hematoxylin and eosin, with Hale's colloidal iron technique (12) or immunostaining with anti-parvalbumin monoclonal antibody (clone PA-235, SIGMA Chemical, St. Louis, MO; dilution, 1:1000), anti-calbindin-D28K monoclonal antibody (Swant, Bellinzona, Switzerland; dilution, 1:200) and rabbit anti-calretinin antibody (Swant; dilution, 1:2000). To characterize the mitochondrial content of renal neoplasms, we used an anti-mitochondrial monoclonal antibody (clone 113-1, BIOGENEX, S. Ramon, CA; dilution, 1:1600).…”

“…Several features have been proposed to accurately recognize chromophobe carcinoma, includ-ing histochemical, immunohistochemical, genetic, and ultrastructural findings (4,(7)(8)(9)(10)(11)(12)(13)(14). In particular, chromophobe renal carcinoma is characteristically stained by Hale's colloidal iron (10,12), immunoreacts with anti-E-cadherin (14) and antimitochondrial 113-1 (11) antibodies, and shows hypodiploidy caused by frequent loss of many different chromosomes (8,9).…”

“…In particular, chromophobe renal carcinoma is characteristically stained by Hale's colloidal iron (10,12), immunoreacts with anti-E-cadherin (14) and antimitochondrial 113-1 (11) antibodies, and shows hypodiploidy caused by frequent loss of many different chromosomes (8,9).…”

Renal cell neoplasm of oncocytosis: a type of unclassified renal cell carcinoma

“…Histologically, there are 2 variants: one is the typical variant and the other is eosinophilic [5]. Chromophobe cells show a positive reaction for the colloidal iron staining [6].…”

“…On the surface of the wall, a nodular change (arrow) was observed reaction for CK7 is the characteristic of chromophobe renal cell carcinoma [7,8]. The weak reaction for c-kit and the coexistence of cells with a positive reaction for vimentin in addition to a negative reaction in the colloidal iron staining were observed: these results were thought to be in opposition to chromophobe renal cell carcinoma [6,8]. The tumor consisted of eosinophilic cells without pale cells.…”