With the increase in use of CT and ultrasound, more than 50% of kidney tumors are detected by coincidence during examination for other conditions.
The tumor normally develops gradually and may be asymptomatic and non-palpable until the disease is advanced. The tumor may be very large before causing any symptoms. Only when the tumor has infiltrated the calyces and renal pelvis will hematuria appear. If the tumor does not penetrate the urinary tracts, it can infiltrate the capsule and infiltrate around nerves. This may cause local pain or radiating pain in the areas of the nerve supply (flanks, lower extremities). Sometimes, the local tumor will not cause symptoms. The patient may, however, have palpated the tumor himself and requested examination.
At other times the symptoms initiate from bone metastases.
In a patient with hematuria, especially in combination with high sedimentation rate and paraneoplastic symptoms such as fever, weight loss, reduced general health and/or flank pain, a renal tumor should always be suspected. Anemia is also relatively common in kidney cancer.
Twenty-five to thirty percent of patients are diagnosed due to symptoms from metastasis.
Ten to forty percent of the patients may have paraneoplastic symptoms, even if metastases are not present.