Renal cell carcinoma
Renal cell carcinoma is the most common kidney cancer, arising from renal tubular epithelium (most often clear cell), and is now diagnosed incidentally on imaging in most patients rather than through the classic triad of flank pain, hematuria, and mass. Contrast CT or MRI showing an enhancing solid renal mass is usually sufficient to diagnose and stage disease, and treatment is surgical for localized tumors versus tyrosine kinase inhibitors and immune checkpoint inhibitors for metastatic, chemo- and radio-resistant disease.
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What this article covers
- Overview
Definition: renal cell carcinoma (RCC) is a malignant epithelial tumor arising from the renal tubular epithelium, most often in the renal cortex, and is the most common primary kidney cancer.
- Epidemiology
Incidence at presentation: roughly 30% of patients have metastatic disease already present at diagnosis, most commonly to lung, liver, bone, or brain.
- Risk factors
Smoking: the strongest modifiable risk factor.
- Pathophysiology
Site of origin: tumors arise from the epithelium of the proximal convoluted tubule (clear cell subtype) in the renal cortex.
- Clinical features
Incidental discovery is now the most common presentation: an asymptomatic renal mass found on abdominal imaging obtained for an unrelated indication.
- Differential diagnosis
Simple renal cyst: a smooth, thin-walled, homogeneous fluid collection with no solid components and no contrast enhancement, distinguishing it from a solid enhancing mass.
- Diagnosis
Established by imaging: a solid, enhancing renal mass on multiphase contrast-enhanced CT or MRI is usually sufficient to diagnose and stage RCC without tissue confirmation.
- Management
Localized disease, small renal mass under 4 cm: active surveillance with repeat imaging at 3 to 6 month intervals is reasonable, escalating to intervention if the mass grows rapidly; thermal ablation…
- Complications
Distant metastasis: lung, bone, liver, and brain, present in roughly 30% of patients at diagnosis.
- Prognosis
Stage at diagnosis is the dominant prognostic factor: localized disease treated surgically has a favorable outlook, while metastatic disease at presentation (roughly 30%) carries a substantially worse prognosis.
- Prevention
Smoking cessation: the single most important modifiable risk-reduction measure, given smoking is the strongest modifiable risk factor.
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