Uncommon Tumors of the Kidney

Tumors of the kidney account for about 3% of adult malignancies. About 60,920 new cases of kidney cancer (37,120 in men and 23,800 in women) were estimated by the American Cancer Society for the year 2011. Renal cell carcinomas constitute the bulk of these malignancies and historically they were widely known as hypernephroma, a term that was coined by Grawitz in the 19th century, reflecting his belief that they arose from the adrenal gland. Renal cell carcinomas are derived from the epithelial cells of renal tubules and account for more than 80% of primary renal malignant neoplasms. Transitional cell carcinomas, although arising in the renal pelvis, are frequently classified as renal tumors, and account for 7-8%. Other tumors, such as oncocytomas, collecting duct carcinomas of Bellini, and renal sarcomas, are uncommon but are becoming more frequently recognized pathologically. Nephroblastoma (Wilms tumor) is common in children and accounts for 5-6% of all primary renal tumors. This chapter focuses on the classification, pathology, genetics, clinical and radiographic manifestations, and surgical and systemic management of the less common malignant and benign tumors of the kidney.