Tumours of the kidney and urinary tract

Question 1

Tumours of the kidney and urinary tract

Introduction

Answer 1

Two types of cancer arise from the renal parenchyma:

• Renal cell carcinomas (also known as renal adenocarcinomas and previously as hypernephromas) are confined to adults
• Nephroblastomas (Wilms’ tumours) are developmental in origin
• present in infancy or early childhood

Question 2

Renal cell carcinoma

Answer 2

Histological classification of adult renal tumours of the Union Internationale Contre le Cancer (UICC):

​A. Malignant:

• Conventional clear cell carcinoma (70–80%)
• Papillary or tubulo-papillary renal carcinoma (10–15%)
• Chromophobe renal carcinoma (5%)
• Collecting duct carcinoma (rare)

B. Benign:

• Oncocytoma
• Papillary or tubular adenoma
• Angiomyolipoma (may be neoplastic or hamartomatous)

Question 3

Renal cell carcinoma

Pathology of renal cell carcinoma

Answer 3

• originates in renal tubules
• Tumour cells are characteristically large and polygonal, with clear cytoplasm representing accumulation of glycogen and lipid
• known pathologically as clear cell carcinomas
• Advanced renal cell carcinoma characteristically extends into the lumen of the renal vein and into the inferior vena cava
• spread is typically to lung, liver and bone. Lung metastases are often typical discrete ‘cannonball secondaries’

Question 4

Renal cell carcinoma

Staging of renal cell carcinoma

Answer 4

• Stage I tumours are confined by the renal capsule;
• stage II tumours have penetrated the renal capsule but remain confined by Gerota’s perinephric fascia;
• stage III tumours have renal vein involvement or nodal spread;
• stage IV have distant metastases.

Question 5

Renal cell carcinoma

Clinical features of renal cell carcinoma

Answer 5

• triad of haematuria, a mass and flank pain;
• diagnosis is made incidentally by discovering a tumour on ultrasonography or CT scanning
• Renal cell carcinomas often become large before diagnosis owing to their retroperitoneal position

Uncommon presentations:

• Iron deficiency anaemia
• Polycythaemia due to erythropoietin production
• Hypertension due to renin production
• Hypercalcaemia due to parathormone-like protein production
• Pyrexia of unknown origin
• Elevated erythrocyte sedimentation rate
• Secondary lesions (e.g. ‘cannonball’ lesions on chest X-ray, pathological fractures)

Question 6

Urothelial carcinoma (transitional cell carcinoma)

Answer 6

• Tumours of urothelium are common
• Histologically, they are nearly all urothelial carcinomas (UCs); other than rarities, the rest are squamous cell carcinomas (7%) or adenocarcinomas (1%)
• Most arise primarily in the bladder but they also occur in the pelvicalyceal system and ureters and rarely in the urethra
• Men are affected three times more often than women. UC is at least four times more common than renal cell carcinoma.
• Cigarette smoking is associated with a four-fold increase in incidence of urothelial tumours; this is probably mediated by urinary excretion of inhaled carcinogens
• strongly associated with exposure to industrial carcinogens, once widely used in the rubber, cable, dye and printing industries

Question 7

Urothelial carcinoma

Clinical features of urothelial carcinoma

Answer 7

• presents with painless haematuria
• Very occasionally, an upper tract lesion may cause ureteric colic (clot colic) and long stringy clots are seen in the urine
• If bleeding is gross, clots may cause ureteric obstruction. Rapid bleeding from a bladder tumour may cause clot retention, i.e. acute retention of urine due to clot obstruction
• predispose to infection; unexplained recurrent urinary tract infections need investigating to exclude UC as a cause

Question 8

Urothelial carcinoma

Staging of urothelial tumours of the bladder

Answer 8

• Staging is achieved mainly by cystoscopic examination and palpation under anaesthesia, combined with histological examination of resected specimens.
• TNM clinical system widely used in staging bladder tumours

Question 9

Urothelial carcinoma

Management of urothelial carcinoma

Bladder Tumours

Answer 9

• Urothelial carcinomas of bladder - diff morphological types, from small, discrete, multiple, frond-like lesions through to extensive papilliferous or flat tumours
• Four-quadrant biopsy of the rest of the bladder can help formulate a treatment plan and estimate prognosis
• If papillary tumours coexist with carcinoma-in-situ (CIS), long-term prognosis is poor
• treated by immunotherapy with a course of intravesical BCG to stimulate local immunity
• if CIS persists, then total cystectomy is the treatment of choice
• complete removal of tumour tissue by cystoscopic transurethral resection of bladder tumour (TURBT)

Question 10

Urothelial carcinoma

Management of urothelial carcinoma

Urothelial tumours of the upper tract

Answer 10

• Treatment usually requires excision of the whole upper tract on the affected side including kidney, ureter and a cuff of bladder wall surrounding the distal ureter.
• However, some small, isolated renal pelvic tumours can be dealt with endoscopically via a nephroscope passed percutaneously into the pelvicalyceal system or by laser ablation via a fibreoptic flexible ureteroscope