The Distribution of Histological Subtypes of Renal Tumors by Decade of Life Using the 2004 WHO Classification

Abstract

The 2004 World Health Organization histological classification of renal tumors reflects our understanding of the underlying molecular determinants of renal tumors. We reviewed all partial and radical nephrectomy specimens at Barnes-Jewish Hospital to determine if the distribution of renal tumor histological subtypes varies by decade of life using the new scheme. A total of 1,043 consecutive cases of renal masses operated on for presumed malignancy from 1989 to 2003 were identified. All specimens were rereviewed by a single pathologist (MFS) and classified by the 2004 WHO scheme. In addition to decade of life and histological subtype, gender, tumor size and pathological tumor stage were analyzed. Analysis demonstrated an association between histological subtype and decade of life (p <0.001). The proportions of clear cell renal cell carcinoma (p = 0.008) and angiomyolipoma (p <0.001) decreased while the proportions of oncocytoma (p <0.001) and papillary renal cell carcinoma (p = 0.005) increased with increasing decade of life. The proportions of chromophobe (p = 0.181) and unclassified (p = 0.660) renal cell carcinoma did not change with increasing decade of life. In addition, younger patients were more likely to have larger tumors (p = 0.019) and metastatic disease at diagnosis (p = 0.017), while gender (p = 0.809) and tumor stage (p = 0.334) were not associated with increasing decade of life. This study provides baseline histological subtypes by decade for the most common renal tumors using the 2004 WHO histological classification. Clinicians may consider using these trends along with imaging, history and physical examination to counsel patients before recommending treatment.