Surgery chapters
Renal tumours
Benign kidney tumours (angiomyolipoma, oncocytoma, adenoma), renal cell carcinoma (risk factors, VHL, presentation, paraneoplastic features, staging, surgery and targeted therapy), upper tract urothelial carcinoma and Wilms tumour.
- Renal cell carcinoma arises from proximal tubule epithelium; clear-cell is the commonest type and is linked to loss of the VHL gene on 3p; smoking, obesity and hypertension are risk factors.
- The classic triad (haematuria, loin pain, mass) is seen in under 10%; most tumours are found incidentally on scans, and paraneoplastic features (polycythaemia, hypercalcaemia, fever) are common.
- Stage with contrast CT chest, abdomen and pelvis; treat localised disease by partial nephrectomy (small tumours) or radical nephrectomy; metastatic disease gets targeted therapy (TKIs, mTOR, immunotherapy).
On this page
Overview
Most solid kidney masses in adults are renal cell carcinomas (RCC). Because of widespread ultrasound and CT, many are now found by chance, while still small and curable. The surgeon's job is to tell benign from malignant, stage the disease, and remove the tumour while keeping as much kidney as possible.
Other important tumours are urothelial (transitional cell) carcinoma of the renal pelvis and ureter and, in children, Wilms tumour.
Classification of renal tumours
| Benign | Malignant (primary) | Secondary |
|---|---|---|
| Angiomyolipoma | Renal cell carcinoma (adults) | Lymphoma, lung, breast (uncommon) |
| Oncocytoma | Urothelial carcinoma of renal pelvis | |
| Cortical adenoma (small, pea-like) | Wilms tumour (children) | |
| Angioma (haematuria in young adults) | Sarcoma (rare) |
Benign tumours
Angiomyolipoma (AML)
- Made of blood vessels, smooth muscle and fat.
- Often linked with tuberous sclerosis (multiple, bilateral AMLs with epilepsy, learning difficulty, facial angiofibromas).
- Fat in the mass on CT is diagnostic; bright on ultrasound.
- Risk of spontaneous bleeding (retroperitoneal haemorrhage) in large lesions; treated by embolisation or partial nephrectomy.
Oncocytoma
- Benign; well circumscribed, mahogany-brown, often with a central scar.
- Hard to tell from RCC on imaging, so it is often removed.
Renal cell carcinoma (RCC)
Also called hypernephroma or Grawitz tumour (old names).
Epidemiology
- About 2% of all cancers.
- Male:female about 2:1; median age at diagnosis about 64 years.
- Hereditary forms make up about 3–5%; consider them in patients diagnosed young (under about 46).
Risk factors
- Smoking, obesity, hypertension, older age, male sex.
- Chronic kidney disease, long-term dialysis (acquired cystic disease), kidney transplantation.
- Family history (about twofold risk).
- Inherited syndromes:
| Syndrome | Gene | Kidney tumour | Other features |
|---|---|---|---|
| von Hippel–Lindau | VHL (3p) | Clear-cell RCC, often bilateral and multiple; renal cysts | Haemangioblastoma (cerebellum, retina), phaeochromocytoma, pancreatic cysts and tumours, epididymal cystadenoma |
| Hereditary papillary RCC | MET | Papillary type 1 | — |
| Hereditary leiomyomatosis and RCC | FH | Papillary type 2 | Skin and uterine leiomyomas |
| Birt–Hogg–Dubé | FLCN | Chromophobe, oncocytoma, hybrid | Skin fibrofolliculomas, lung cysts, pneumothorax |
| Tuberous sclerosis | TSC1/TSC2 | Angiomyolipoma, cysts, some RCC | Facial angiofibroma, epilepsy, ash-leaf macules |
Pathology
- Arises from the epithelium of the proximal convoluted tubule.
- Clear-cell RCC (commonest; most deaths): golden-yellow cut surface with haemorrhage, necrosis and cysts. Cells look clear because they are packed with glycogen and lipid.
- Papillary RCC (types 1 and 2): the next most common.
- Chromophobe RCC: better prognosis.
- Collecting duct and medullary carcinoma (young people with sickle cell trait): rare and aggressive.
- Any type can show sarcomatoid change (poor prognosis).
- Fuhrman grade 1–4 is based on nuclear size and nucleoli.
Clear-cell RCC carries loss of the VHL tumour-suppressor gene on 3p in both inherited (von Hippel–Lindau) and most sporadic cases. Bilateral or multiple tumours in a young patient suggest the inherited form.
Spread
- Direct: through the capsule into perinephric fat and Gerota's fascia; into the adrenal.
- Venous: a characteristic tendency to grow as a tumour thrombus into the renal vein and IVC, sometimes up to the right atrium.
- Lymphatic: hilar and para-aortic nodes.
- Blood-borne: lungs (commonest), bone (lytic), liver, brain.
Clinical features
- Incidental finding on imaging: now the commonest presentation.
- Classic triad: haematuria, loin pain, loin mass — found in fewer than 10% and usually means advanced disease.
- Varicocele: a left tumour invading the left renal vein blocks the left testicular vein; the varicocele appears late in life and does not empty on lying down.
- Symptoms of metastases: cough or haemoptysis, bone pain or fracture.
- Paraneoplastic syndromes (from hormones and cytokines):
| Syndrome | Mechanism |
|---|---|
| Polycythaemia (erythrocytosis) | Tumour makes erythropoietin |
| Hypercalcaemia | PTH-related peptide, bone metastases |
| Fever, weight loss, raised ESR | Cytokines |
| Hypertension | Renin |
| Anaemia | Chronic disease (an adverse sign) |
| Stauffer syndrome | Reversible liver dysfunction without liver metastases |
A young man with polycythaemia, haematuria and a loin mass has RCC until proven otherwise. A new left varicocele in an older man needs a renal ultrasound.
Most RCCs today present without any symptoms. Do not wait for the triad; it is a late and uncommon finding.
Investigations
- Ultrasound: solid versus cystic mass.
- Contrast CT of chest, abdomen and pelvis: diagnosis and staging (size, fat invasion, renal vein and IVC thrombus, nodes, lung and liver metastases).
- MRI: extent of venous tumour thrombus; useful if contrast cannot be given.
- Bone scan only if bone symptoms or a raised alkaline phosphatase; PET is not used for routine staging.
- Bloods: FBC (polycythaemia or anaemia), calcium, U&E, LFT.
- Biopsy: not routine for a typical enhancing mass; used for small masses before ablation or surveillance, or before systemic therapy.
- Complex cysts are graded by Bosniak (III about 50% malignant, IV about 100%).
Staging (simplified)
| Stage | Extent |
|---|---|
| I | Confined to kidney, 7 cm or less |
| II | Confined to kidney, over 7 cm |
| III | Into major veins or adrenal, or regional nodes, but inside Gerota's fascia |
| IV | Beyond Gerota's fascia or distant metastases |
Treatment of localised RCC
Surgery is the mainstay; RCC is not treated by radiotherapy for cure.
| Operation | Details and indications |
|---|---|
| Partial nephrectomy (nephron-sparing) | Standard for T1 tumours (up to 7 cm) where technically feasible. Absolute indications: solitary kidney, bilateral tumours, VHL. Relative: conditions that threaten renal function (diabetes, hypertension, stones). Open, laparoscopic or robotic. Complications: bleeding, urine leak (fistula) |
| Radical nephrectomy | Removes kidney, perinephric fat inside Gerota's fascia, adrenal and regional nodes. The adrenal may be spared for small lower-pole tumours; node dissection if nodes look involved. Laparoscopic when possible |
| With venous thrombus | Removal of renal vein or IVC thrombus; cardiopulmonary bypass if above the diaphragm |
| Active surveillance | Small masses in elderly or unfit patients; intervene if growing beyond 3–4 cm or more than 0.5 cm a year |
| Ablation (radiofrequency or cryotherapy) | Small tumours in unfit patients; percutaneous or laparoscopic; higher local recurrence than surgery |
At the renal hilum, from front to back, lie the vein, artery, then pelvis.
Partial nephrectomy gives the same cancer control as radical nephrectomy for small (T1) tumours while preserving renal function.
Metastatic RCC
- Cytoreductive nephrectomy helps selected fit patients with a large primary and limited metastases.
- Targeted therapy against the VEGF pathway: tyrosine kinase inhibitors (sunitinib, pazopanib, sorafenib, axitinib, cabozantinib) and bevacizumab.
- mTOR inhibitors: everolimus, temsirolimus.
- Immune checkpoint inhibitors: nivolumab, pembrolizumab, alone or in combination.
- Solitary metastases can sometimes be excised.
RCC = "Really Cunning Cancer": it hides (incidental), mimics (paraneoplastic), and creeps up veins (renal vein and IVC thrombus).
Upper tract urothelial carcinoma (renal pelvis and ureter)
- Accounts for about 5–10% of urothelial (transitional cell) cancers.
- Same risk factors as bladder cancer: smoking, aromatic amines, analgesic (phenacetin) abuse, Balkan nephropathy.
- Multifocal "field change": about 40% later develop bladder tumours, so the bladder must be watched by cystoscopy.
- Presents with visible haematuria, colic from clots, or a filling defect on CT urography; cytology may be positive.
- Diagnosis: CT urography, ureteroscopy with biopsy.
- Treatment: nephroureterectomy with excision of a cuff of bladder around the ureteric orifice. A single post-operative dose of intravesical mitomycin C reduces later bladder tumours. Small low-grade tumours may be treated endoscopically.
For a renal pelvis urothelial tumour, a simple nephrectomy is wrong. The whole ureter and its bladder cuff must go, because tumour often recurs in the stump.
Wilms tumour (nephroblastoma)
- Commonest renal tumour of childhood; usually in the first 5 years.
- Arises from embryonic nephrogenic tissue (mixed blastemal, stromal and epithelial elements).
- Associations: WT1 gene, aniridia (WAGR), hemihypertrophy (Beckwith–Wiedemann).
- Presents as a large, smooth abdominal mass in a well or unwell child; hypertension in some; haematuria is a poor sign (tumour in the pelvis).
- Does not usually cross the midline and is distinguished from neuroblastoma (which crosses the midline, calcifies and raises urinary catecholamines).
- Spreads early to the lungs; liver, bone and brain spread is rare.
- Treatment: in specialist centres; chemotherapy then nephrectomy for most unilateral tumours; partial nephrectomy in bilateral disease.
- Prognosis: about 80% long-term survival; worse with metastases and in older children.
Expect: RCC origin (proximal tubule), clear-cell type and VHL on 3p, risk factors (smoking, obesity, hypertension, dialysis), the triad in under 10%, paraneoplastic polycythaemia and hypercalcaemia, a left varicocele from renal vein invasion, spread into the renal vein and IVC, CT staging and Gerota's fascia, partial nephrectomy indications (solitary kidney, bilateral, VHL), targeted therapy for metastases, fat on CT meaning angiomyolipoma with tuberous sclerosis, nephroureterectomy for upper tract TCC, and Wilms tumour in children under 5.
Quick revision
- RCC: proximal tubule; clear-cell commonest; VHL gene 3p.
- Risks: smoking, obesity, hypertension, dialysis, family history.
- Mostly incidental; triad under 10%.
- Paraneoplastic: polycythaemia (EPO), hypercalcaemia, fever, Stauffer syndrome.
- Left varicocele that persists supine → look at the left kidney.
- Spread: renal vein and IVC thrombus; lungs commonest distant site.
- Stage I ≤7 cm, II >7 cm, III veins/nodes inside Gerota, IV beyond Gerota or metastases.
- Partial nephrectomy for small tumours; radical nephrectomy otherwise; TKIs for metastases.
- AML = fat (tuberous sclerosis); oncocytoma = central scar.
- Upper tract TCC → nephroureterectomy + bladder cuff; watch the bladder.
Written by The House Job from standard references (Bailey & Love; Kumar and Clark's Clinical Medicine).
FAQ
What is the commonest way renal cell carcinoma is found today?
As an incidental mass on an ultrasound or CT done for another reason. The classic triad of haematuria, loin pain and mass appears in fewer than one in ten patients.
Why can a kidney cancer cause polycythaemia?
The tumour can make erythropoietin, which drives red cell production. Hypercalcaemia, fever and hypertension are other paraneoplastic effects.
When is partial rather than radical nephrectomy chosen?
For small tumours of 7 cm or less where feasible, and always when the patient has only one kidney, tumours in both kidneys or von Hippel–Lindau disease.
How is a Wilms tumour told apart from a neuroblastoma?
A Wilms tumour arises inside the kidney and usually stays on one side of the midline, while a neuroblastoma often crosses the midline, calcifies and raises urinary catecholamines.