Conservative renal cell cancer surgery in elective conditions can be applied if the tumor is solitary and well delineated on the CT scan and easily resectable within a rim of healthy parenchyma. A number of solid tumors will prove not to be malignant on definite pathological examination. The radiological preoperative differential diagnosis of a small renal mass is not always obvious. The efficacy of fine-needle aspiration cytology in recognizing the pathology of the tumor before surgery is limited and major complications have been reported. Moreover, it can render a conservative surgical procedure less safe. Thus fineneedle aspiration cytology is not recommended if conservative surgery is planned, unless renal involvement by metastasis or lymphoma is suspected.