[822] Comparison of Putative Renal Cell Carcinoma (RCC) Immunohistochemical (IHC) Markers in Primary Adrenal Cortical Lesions (ACL) and Metastatic RCC: A Tissue Microarray Study of 246 Cases
JK McKenney, M Fujiwara, JP Higgins, JV Bonventre, N Gokden, AR Sangoi. Stanford, Stanford, CA; Brigham and Women's Hospital, Boston, MA; UAMS, Little Rock, AR
Background: Given their morphologic overlap, differentiating primary ACL from metastatic clear cell RCC (CC-RCC) can be challenging, particularly on a small biopsy sample. A formal IHC study comparing the sensitivity and specificity of newer, novel RCC markers in this distinction has not been previously reported.
Design: IHC analysis was performed on 61 ACL (41 cortical adenomas, 4 cortical adenomas of uncertain malignant potential, 7 cortical carcinomas, 6 cortical hyperplasias, 3 cortical rests) and compared with 185 metastatic CC-RCC using tissue microarray technology with antibodies recently described in RCC (CAIX, HNF-1beta, and hKIM-1). CC-RCCs were classified as well differentiated (WD) in cases where morphologic features strongly suggested CC-RCC or poorly differentiated (PD) when RCC would not have been suspected by morphology alone. Both staining intensity and extent were semiquantitatively scored on duplicate sections (0-3+).
Results: IHC findings are summarized in Table 1. Specificity for metastatic CC-RCC versus ACL is listed in Table 2. The staining differences among the various ACL studied were not statistically significant, but both lesions with immunoreactivity to CAIX were adrenal cortical carcinomas.
Immunoreactivity in ACL and CC-RCC | CAIX | HNF-1beta | hKIM-1 | | CC-RCC (overall) | 162/184 (88%) | 156/184 (85%) | 170/185 (92%) | | CC-RCC (WD) | 121/133 (91%) | 113/133 (85%) | 122/133 (92%) | | CC-RCC (PD) | 41/51 (80%) | 43/51 (84%) | 48/52 (92%) | | ACL | 2/61 (3%) | 0/61 (0%) | 0/61 (0%) |
| Specificity for CC-RCC | | CAIX | 97% | | HNF-1beta | 100% | | hKIM-1 | 100% |
Conclusions: The recently described antibodies CAIX, HNF-1beta, and hKIM-1 are sensitive and specific immunohistochemical markers of CC-RCC in the distinction from ACL. HNF-1beta and hKIM-1 appear to be more specific than CAIX in the setting of an adrenal cortical carcinoma, and hKIM-1 has the highest sensitivity in metastatic poorly differentiated RCC.
Category: Genitourinary (including renal tumors)
Tuesday, March 10, 2009 1:00 PM
Poster Session IV # 136, Tuesday Afternoon
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