[811] Light and Immunohistochemical Characterization of Renal Cell Carcinoma under 40. A Multicenter Study of 114 Cases

JI Lopez, H Garcia, I Anton, A Ugalde, A Banos, JM Onate, J Escandon, V Velasco, JR Vilanova. Hospital de Cruces, Basque Country Univ, Barakaldo, Spain; Hospital 12 de Octubre, Complutensis Univ, Madrid, Spain; Centro POVISA, Vigo, Spain; Hospital de Basurto, Basque Country Univ, Bilbao, Spain; Hospital General Yage, Burgos, Spain; Hospital del Rio Hortega, Valladolid, Spain; Hospital Peset, Valencia Univ, Valencia, Spain

Background: Renal cell carcinoma (RCC) is a rare event in young adults, very few large series being published so far. The aim of this study is to review the histological characteristics and the immunohistochemical profile of a large series of RCC under the age of 40.
Design: A total of 114 cases were collected from 7 hospitals in Spain. Five different categories were considered by light microscopy: Clear cell renal cell carcinoma (CCRCC), papillary renal cell carcinoma (PRCC), chromophobe renal cell carcinoma (ChRCC), clear cell papillary renal cell carcinoma (CCPRCC), biphasic renal cell carcinoma [carcinomas with two different, but clearly recognized, histologies (BRCC)] and unclassified renal cell carcinoma (URCC). Fuhrman's grade was evaluated only in CCRCC. CD10, EMA, CK7, CK20, CD15, CD117, AMACR, CAM 5.2, 34betaE12, e-cadherin, and Melan-A were systematically tested in all cases.
Results: Males predominated (83M/31F), average age of 32,9 years (range, 14-39). Organ confined disease (pT1/2) was observed in 91% of the cases. pN+ status was detected in 2,6% and pM+ in 0,9%. Fuhrman's grade in CCRCC group was G1: 15%, G2: 53%, G3: 23%, G4: 9%.

Histological typing and immunohistochemical profile

Histology (n)	CD10 (n/%)	EMA (n/%)	CK7 (n/%)	CD15 (n/%)	AMACR (n/%)	CAM 5.2 (n/%)	E-cadh (n/%)
CCRCC (58)	53/91	52/89	12/20	35/60	6/10	40/69	10/17
PRCC (9)	4/44	8/89	4/44	5/55	9/100	8/89	2/22
ChRCC (16)	5/31	16/100	12/75	0/0	3/19	15/94	14/87
CCPRCC (12)	9/75	9/75	5/42	7/58	8/67	9/75	4/33
BRCC (4)	4/100	4/100	2/50	4/100	0/0	4/100	3/75
URCC (15)	11/73	14/93	2/13	6/40	2/13	11/73	11/73

Most significant markers in CCRCC, PRCC and ChRCC in bold. CCPRCC results in italic. The results of CK20, CD117, 34bE12 and Melan-A were not contributory


Conclusions: CCRCC account for only 50% of RCC in this age group, with a significant number of ChRCC and URCC cases. URCC is an odd group with oncocytic changes and high grade features. CCPRCC, a newly proposed entity, represent a relevant proportion of cases and show mixed characteristics between CCRCC and PRCC.
Category: Genitourinary (including renal tumors)

Tuesday, March 10, 2009 9:30 AM

Poster Session III # 108, Tuesday Morning