[1005] Immunohistochemical (IHC) Expression of Ulex Europaeus Agglutinin-1 (UEA-1) in the Spectrum of Adult Renal Epithelial Neoplasms – A Study of 165 Cases

M Vankalakunti, DE Westfall, RS Parakh, R Gupta, RB Shah, M Amin, AM Gown, LC Goldstein, MB Amin. Cedars-Sinai Medical Center, Los Angeles, CA; University of Michigan, Ann Arbor, MI; William Beaumont Hospital, Royal Oak, MI; PhenoPath Laboratories, Seattle, WA

Background: UEA-1, a marker selectively expressed by principal cells of the collecting duct in the normal kidney, is regarded as an important diagnostic adjunct for collecting duct carcinoma (CDC), a rare and aggressive subtype of renal cell carcinoma (RCC). The specificity of this marker for CDC has not been evaluated in the context of the wide spectrum of RCC described in the recent WHO (2004) classification and RCC subtypes that have been described subsequently.
Design: Tissue microarray (TMA) and conventional paraffin block sections from 165 renal tumors, including clear cell RCC (21;12), papillary RCC (23;10), chromophobe RCC (19;10), oncocytoma (20;10), hybrid oncocytic tumor (7;0), CDC (0;5), renal medullary carcinoma (RMC) (0;2), sarcomatoid RCC, NOS (0;5), mucinous tubular spindle cell carcinoma (0;3), translocation associated RCC (2;2), acquired cystic disease associated RCC (0;5), clear-cell papillary RCC (0;2) and urothelial carcinoma of renal pelvis (UCa) (0;8) were immunostained for UEA-1 (1:250; Vector Laboratories).
Results: UEA-1 showed strong membranous and cytoplasmic reactivity in CDC (5/5, 100%); RMC (3/3, 100%); UCa (7/8, 87.5%); chromophobe RCC (24/29, 83%); oncocytoma (4/30, 13%); hybrid oncocytic tumor (2/7, 28.5%); mucinous tubular spindle cell carcinoma (1/3, 33%); acquired cystic associated RCC (1/5, 20%); and papillary RCC (2/33, 6%). UEA-1 was diffusely positive in CDC, RMC and UCa; it showed patchy positivity in other tumors expressing the antibody. Differences in IHC staining pattern did not appear to correlate with Fuhrman nuclear grade or type of specimen analyzed (TMA vs paraffin block). Clear cell RCC, clear-cell papillary RCC and sarcomatoid RCC, NOS did not express UEA-1. In the normal kidney, UEA-1 selectively stained the collecting duct epithelium. Normal blood vessels served as positive internal controls in all cases.
Conclusions: 1) UEA-1 IHC in adult renal epithelial neoplasia is not specific for CDC, as it is expressed by other renal tumors histogenetically related to the distal nephron; 2) UEA-1 IHC may have a role as a marker within a panel to distinguish chromophobe RCC from oncocytoma; 3) strong positivity of UEA-1 in CDC and RMC suggests close interrelationship between these aggressive and rare subtypes of RCC.
Category: Genitourinary (including renal tumors)

Wednesday, March 24, 2010 9:30 AM

Poster Session V # 109, Wednesday Morning


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