13 Renal Cell Carcinoma
Incidence of renal cell carcinoma (RCC) has been increasing by 2 to 3% per decade. It is usually found in the developed world. Incidence in Asians is low; it is highest in the United States in African Americans. It is found mostly in patients over 65 years old. Risk factors include smoking, obesity, hypertension and occupational exposure to asbestos, lead, cadmium, petrochemicals. 1 – 3
RCC is derived from the nephron.
There are three major histologic types of RCC:
Clear cell RCC: Derived from proximal tubules, 60 to 70% of cases, sporadic and not linked to syndromes.
Papillary RCC: Derived from proximal tubules, 10 to 15% of cases, less aggressive than clear cell RCC, may be hereditary.
Chromophobe RCC: Derived from cortical collecting duct, 3 to 5% of cases, least aggressive RCC, sporadic but may be associated with Birt–Hogg–Dubé syndrome.
Birt–Hogg–Dubé syndrome: autosomal-dominant mutation in Folliculin (FLCN) gene (17p11), multiple chromophobe RCC, oncocytomas, renal and pulmonary cysts, fibrofolliculomas, spontaneous pneumothorax. 4 , 5
Rare types of RCC include the following:
Multilocular cystic: Favorable prognosis after removal.
Carcinoma of the collecting ducts of Bellini: Very rare, high-grade, poor prognosis, one-third with metastases at diagnosis, two-thirds die within 2 years.
Medullary carcinoma: Very rare, almost all in patients with sickle cell disease or trait, very aggressive, 95% present with metastases, survival of 6 months. 6
Von Hippel–Lindau: Autosomal-dominant mutation in tumor suppressor gene VHL on chromosome 3p25–3p26. Associated are angiomatosis (usually in retina), central nervous system (CNS) or spinal hemangioblastoma, pheochromocytoma, clear cell RCC, pancreatic cysts. Usually multiple small clear cell or papillary RCC. 12
Tuberous sclerosis: Mutation in tuberous sclerosis 1 (TSC1) or tuberous sclerosis 2 (TSC2), which produces hamartin or tuberin, which are tumor suppressors. Associated with hamartomas (especially in CNS where they may be astrocytomas), multiple angiomyolipomas in kidney, polycystic kidney disease, rare clear cell RCC, dermal fibromas, and retinal phakomas, pulmonary lymphangiomyomatosis. 13 , 14
Cowden’s syndrome: Mutation to PTEN (phosphatase and tensin homolog) gene (10q23). Associated with breast tumors, either benign or malignant, thyroid carcinoma, papillary RCC. 15
Familial leiomyomatosis and RCC: Mutation in fumarate hydratase (1q42–1q43). Associated with papillary RCC, collecting duct RCC, leiomyomas of skin or uterus.
Hereditary papillary RCC: Mutation in c-met proto-oncogene (7q31). Associated with multiple bilateral papillary RCC. 16
T1a = Less than 4 cm and confined to kidney.
T1b = Greater than 4 cm but less than 7 cm and confined to kidney.
T2a = Greater than 7 cm but less than 10 cm and confined to kidney.
T2b = Greater than 10 cm and confined to kidney.
T3a = Extension into renal vein or invades perirenal fat but not outside of Gerota’s fascia.
T3b = Extends into inferior vena cava below diaphragm.
T3c = Extends into vena cava/right atrium above diaphragm or invades caval wall.
T4 = Tumor invades beyond Gerota’s fascia or into ipsilateral adrenal gland.