SN5 SHORT NOTE 5M ★ High-yield

Describe carcinoma of the urinary bladder with its aetiology, morphology and clinical features.

Pathology · 2nd Professional — Para-Clinical

Introduction

Urothelial (transitional cell) carcinoma accounts for over 90% of bladder tumours, and may arise anywhere the urothelium is found — renal pelvis, ureter, bladder and proximal urethra.

Male to female ratio about 3:1; usually over 50
A "field change" disease — the whole urothelium is exposed to the same carcinogens, so tumours are frequently multifocal and recurrent, which dictates lifelong surveillance

Aetiology

Factor	Detail
Smoking	The single greatest risk, responsible for about half of cases; a three- to sevenfold increase
Occupational aromatic amines	Beta-naphthylamine and benzidine — aniline dye, rubber, leather, printing and textile industries; latency of 15 to 40 years
Schistosoma haematobium	Chronic infestation causes squamous metaplasia and then squamous cell carcinoma; important in Egypt and parts of Africa
Chronic irritation	Long-term catheterisation, bladder stones, recurrent infection — also predispose to squamous carcinoma
Drugs and radiation	Cyclophosphamide (through acrolein, which also causes haemorrhagic cystitis), phenacetin abuse, pelvic radiotherapy
Other	Bladder exstrophy (adenocarcinoma); urachal remnants (adenocarcinoma)

Morphology and Behaviour

Category	Features	Behaviour
Papillary non-invasive (low grade)	Delicate branching fronds with a fibrovascular core; orderly urothelium	Recurs often but rarely invades; good prognosis
Papillary high grade	Disordered, pleomorphic urothelium with mitoses at all levels	Significant risk of invasion
Carcinoma IN situ (flat)	Flat, high-grade dysplasia with no papillary structure; may look like harmless erythema or be invisible cystoscopically	High risk of progression to invasive disease — far more dangerous than its appearance suggests
Invasive	Invades the lamina propria, then the muscularis propria (detrusor)	Invasion of muscle is the critical prognostic division

CLINICAL PEARL

Muscle invasion is the single most important fact about a bladder tumour.
Non-muscle-invasive disease is managed endoscopically with intravesical treatment and surveillance, and most patients keep their bladder.
Muscle-invasive disease requires radical cystectomy or radiotherapy and carries a far worse prognosis. This is why the resection specimen must include detrusor muscle — a biopsy without it cannot answer the question that matters.

Clinical Features and Investigation

Painless gross haematuria is the classical presentation, present in about 85%; it is often intermittent, and a single episode demands full investigation
Frequency, urgency and dysuria suggest carcinoma in situ or a trigonal tumour, and are easily mistaken for infection
Obstruction of a ureteric orifice causes hydronephrosis and may present as renal impairment
Cystoscopy with biopsy is the definitive investigation; urine cytology is useful for high-grade tumours and carcinoma in situ, which shed abnormal cells, but often misses low-grade papillary tumours
CT urography images the upper tracts, which must always be assessed because of the field effect

Applied Aspects

Painless haematuria in an adult is bladder cancer until proved otherwise — it must never be attributed to infection or to anticoagulation without investigation
Transurethral resection with intravesical BCG or mitomycin for non-muscle-invasive disease; BCG provokes a local immune response and is particularly effective for carcinoma in situ
Lifelong cystoscopic surveillance is essential because of the high recurrence rate; this makes bladder cancer among the most expensive cancers to manage per patient
Radical cystectomy with urinary diversion, or radical radiotherapy, for muscle-invasive disease, with neoadjuvant chemotherapy
Smoking cessation reduces the risk of recurrence as well as of the first tumour, and is part of treatment rather than merely advice
In India, chronic catheterisation, stones and infection make squamous cell carcinoma relatively more common than in Western series

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