Renal cell carcinoma is the most frequent malignant neoplasm and accounts for about 2% of all cancer deaths in both sexes. It has an increased predilection for men, with a male-to-female ratio of about 2:1.
The incidence of this malignancy peaks between the ages of 50 and 70 years. The term hypernephroma originated from the gross appearance of these tumors, which, because of their high lipid content, resemble adrenal tissue.
Some cases of renal cell carcinoma are associated with an abnormality in chromosome 3. Von Hippel-Lindau disease is associated with renal cell carcinoma and is also characterized by an abnormality in chromosome 3. Other features of von Hippel-Lindau disease include spinal and cerebellar hemangioblastomas, renal and pan creatic cysts, retinal angiomas, and pheochromocytomas. Renal cell carcinoma originates from the proximal tubular elements. The tumors usually have three cell types: clear cells, granular cells, and spindle cells. The spindle cell type has extensive nuclear anaplasia and confers a poor prognosis. The tumors are highly vascular, supplied by vessels with thin, amuscular walls. Extension of the tumor into normal renal veins and even into the inferior vena cava is not uncommon. Metastatic spread is chiefly via vascular routes, and the lungs, bone tumors often undergo cystic internal degeneration, thus mimicking benign renal cysts. Calcification within a renal mass, the result of internal necrosis, is a significant radiographic indicator of malignancy. The classic clinical manifestation of renal cell carcinoma a triad of hematuria, flank pain, and palpable flank mass seen in only about 10% of affected patients. However, any one of these features is present in more than half of all patients as an initial manifestation of the tumor. These tumors are commonly diagnosed as incidental findings during radiodiagnostic procedures Renal cell carcinoma is notable for the large number of systemic, extrarenal manifestations of the tumor. Fever is present in about 20% of cases, and an elevated erythrocyte sedimentation rate is present in about 50% of the patients.
Anemia is present in about one third of patients, and polycythemia secondary to increased erythropoietin is striking finding in some eversible hepatic dysfunction has been found, as has peripheral neuropathy. Ectopic hormone syndromes associated with renal cell carcinoma include hypercalcemia from osteoclast-stimulating factors and Cushing’s syndrome from tumor production of an adrenocorticotropic hormone like factor. Hypercalcemia in renal cell carcinoma is frequently associated with bone metastasis of the tumor.
Treatment of renal cell carcinoma requires surgical excision of the tumor, usually by radical nephrectomy.