This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney, Subject name: Pathology
True about RCC is? 
Select and explain. 
A. Most common site is lower lobe of kidney, B. Most common variety is papillary type, C. Invasion of renal vein is more common than renal artery, D. Most common site of metastasis is lymph nodes
C: Invasion of renal vein is more common than renal artery
Answer: C: Invasion of renal vein is more common than renal artery 
Explanation: Ans. is 'c' i.e., Invasion of renal vein is more common than renal artery * Renal cell carcinoma is the most common malignant tumor of kidney. It occurs usually in 6th and 7th decade of life. There is male preponderance.* Important risk factors for RCC are smoking (most significant), obesity, hypertension, asbestos exposure, estrogen therapy, CRF, tuberous sclerosis and familial conditions (Von Hippel-Lindau syndrome).* RCC is an adenocarcinoma and most commonly arises from upper pole.* Clear cell carcinoma is the most common type of renal cancer accounting for about 70% to 80% of the renal cell cancer. Papillary carcinoma, Chromobphobic (oncocytic) carcinoma, Collecting duct (Bellini duct) carcinoma are the other three varities.* The three classical diagnostic features (classical triad) of renal cell carcinoma are costovertebral pain, palpablemass and hematuria. The most reliable of three is hematuria.* The one of the striking characteristics of RCC is to invade renal vein and is associated with poor prognosis.* Metastasis usually occur by hematogenous route to lung (most commonly), bone, lymph nodes, liver, adrenal and brain.