Question 1: Ureteric Calculus
Stem: A 45-year-old man presents with acute, severe right flank pain radiating to the groin. A non-contrast CT KUB (Kidneys, Ureters, Bladder) is performed.
Question: Which of the following is the most specific secondary sign of an obstructing ureteric calculus?
(A) Hydronephrosis. (B) Perinephric fat stranding. (C) Ureteric wall oedema surrounding the calculus (“tissue rim sign”). (D) Renal enlargement. (E) Absence of the calculus (“missed stone”).
Correct Answer: (C) Ureteric wall oedema surrounding the calculus (“tissue rim sign”).
Explanation:
- Why (C) is correct: The “tissue rim sign” refers to the oedematous ureteric wall surrounding an impacted calculus. This sign helps distinguish a calculus (which will have the rim) from a phlebolith (a calcified pelvic vein, which will not have the rim). It is a highly specific secondary sign of a ureteric stone.
- Why (A) is wrong: Hydronephrosis (dilatation of the collecting system) is a common sign but can be caused by other things (e.g., UPJ obstruction, tumour) and may be absent in acute obstruction or dehydration.
- Why (B) is wrong: Perinephric fat stranding (inflammation) is also a common secondary sign but is less specific than the tissue rim sign.
- Why (D) is wrong: Renal enlargement can occur due to oedema but is not specific.
- Why (E) is wrong: While small stones can be missed, this isn’t a sign of obstruction.
Key Points: Obstructing Ureteric Calculus (CT)
- Direct Sign: Visualisation of the calcified stone within the ureter (most common sites: UPJ, pelvic brim, VUJ).
- Secondary Signs:
- Hydronephrosis/Hydroureter (proximal dilatation).
- Perinephric/Periureteric Fat Stranding (inflammation).
- Nephromegaly (renal enlargement).
- “Tissue Rim Sign” (oedematous ureteric wall around the stone – helps differentiate from phlebolith).
Question 2: Transitional Cell Carcinoma (TCC) – Ureter
Stem: A 75-year-old heavy smoker presents with painless haematuria. A CT urogram is performed. The delayed excretory phase images demonstrate focal, irregular thickening of the wall of the distal left ureter, causing an associated filling defect and mild proximal hydroureteronephrosis.
Question: What is the most likely diagnosis?
(A) Ureteric Calculus (B) Transitional Cell Carcinoma (TCC/UCC) (C) Blood Clot (D) Ureteritis Cystica (E) Fibroepithelial Polyp
Correct Answer: (B) Transitional Cell Carcinoma (TCC/UCC).
Explanation:
- Why (B) is correct: TCC (Urothelial Carcinoma) is the most common malignancy of the ureter. It typically presents as focal wall thickening or an intraluminal filling defect on excretory phase imaging. Smoking is a major risk factor, and haematuria is the classic symptom.
- Why (A) is wrong: A calculus would be hyperdense on non-contrast CT and is typically intraluminal, not wall thickening (though it causes secondary wall oedema).
- Why (C) is wrong: A blood clot is a filling defect but would not cause primary wall thickening and should resolve.
- Why (D) is wrong: Ureteritis cystica causes multiple, tiny, smooth submucosal filling defects (cystic change from chronic inflammation), not focal irregular thickening.
- Why (E) is wrong: A fibroepithelial polyp is a rare, benign, elongated, smooth filling defect, typically in the proximal ureter.
Key Points: Ureteric TCC/UCC
- Definition: Malignancy of the urothelium lining the ureter.
- Risk Factors: Smoking, industrial carcinogens, Lynch syndrome.
- Imaging (CT Urogram):
- Focal wall thickening (often eccentric).
- Intraluminal filling defect (sessile or papillary).
- Associated hydroureteronephrosis.
- Note: Often multifocal (“field change”). Look for synchronous tumours in the renal pelvis or bladder.
Question 3: Pelvi-Ureteric Junction (UPJ) Obstruction
Stem: A 25-year-old man presents with intermittent left flank pain, often worse after consuming large amounts of fluid. An ultrasound shows marked left hydronephrosis. A CT urogram confirms gross dilatation of the left renal pelvis and calyces down to the pelvi-ureteric junction, with an abrupt transition to a normal-calibre proximal ureter. No crossing vessel or stone is identified.
Question: What is the most likely diagnosis?
(A) Congenital UPJ Obstruction (B) Vesicoureteric Reflux (VUR) (C) Ureteric Calculus (D) Transitional Cell Carcinoma (TCC) (E) Posterior Urethral Valves
Correct Answer: (A) Congenital UPJ Obstruction.
Explanation:
- Why (A) is correct: This is the classic description of congenital UPJ obstruction, the most common cause of significant hydronephrosis in children (but can present in adults). It’s a functional obstruction at the junction of the renal pelvis and ureter. Imaging shows marked dilatation proximal to the UPJ with an abrupt transition to a normal or collapsed ureter distal to it. Symptoms worsen with high urine flow (Dietl’s crisis).
- Why (B) is wrong: VUR causes dilatation of the ureter and pelvis during voiding due to reflux from the bladder; it doesn’t cause a fixed obstruction at the UPJ.
- Why (C) is wrong: A calculus would be visible as a obstructing density at the UPJ.
- Why (D) is wrong: TCC would be a soft-tissue mass causing the obstruction.
- Why (E) is wrong: Posterior urethral valves cause obstruction at the bladder outlet, leading to bilateral hydroureteronephrosis and a distended bladder.
Key Points: UPJ Obstruction
- Definition: Functional obstruction at the junction of the renal pelvis and ureter. Most common cause is congenital (intrinsic stenosis).
- Clinical: Often presents in childhood, but can present in adults with flank pain (Dietl’s crisis), stones, or infection.
- Imaging:
- Marked hydronephrosis down to the UPJ.
- Abrupt transition to a normal-calibre ureter.
- Delayed excretion of contrast on CTU/IVU.
Question 4: Retroperitoneal Fibrosis (Ormond’s Disease)
Stem: A 60-year-old man presents with non-specific back pain and renal impairment. A CT scan reveals a diffuse, plaque-like soft-tissue mass encasing the infra-renal aorta and IVC. This mass extends laterally to encase both ureters, causing bilateral hydroureteronephrosis. Notably, the aorta itself is not significantly narrowed or displaced anteriorly by the mass.
Question: What is the most likely diagnosis?
(A) Retroperitoneal Fibrosis (Ormond’s Disease) (B) Retroperitoneal Lymphoma (C) Retroperitoneal Sarcoma (D) Aortitis (E) Bilateral Psoas Abscesses
Correct Answer: (A) Retroperitoneal Fibrosis (Ormond’s Disease).
Explanation:
- Why (A) is correct: This is the classic appearance. Retroperitoneal fibrosis (RPF) is a rare condition causing proliferation of fibrous tissue in the retroperitoneum. It typically forms a plaque-like mass centred on the infra-renal aorta/IVC, which encases but does not typically displace the great vessels. Crucially, it extends laterally to encase and medially deviate the ureters, causing obstruction. Most cases are idiopathic, but it can be secondary to drugs, malignancy, or inflammation.
- Why (B) is wrong: Lymphoma typically presents as discrete, bulky nodes that displace the vessels anteriorly.
- Why (C) is wrong: Sarcoma is usually a large, focal, heterogeneous mass.
- Why (D) is wrong: Aortitis involves thickening of the aortic wall itself, not an external plaque.
- Why (E) is wrong: Abscesses are rim-enhancing fluid collections centred on the psoas muscles.
Key Points: Retroperitoneal Fibrosis (RPF)
- Definition: Proliferation of fibrous tissue in the retroperitoneum.
- Cause: Mostly idiopathic (~70%); secondary causes include drugs (methysergide), malignancy, infection, inflammation.
- Imaging:
- Plaque-like soft-tissue mass encasing the infra-renal aorta/IVC.
- Encasement and medial deviation of the ureters, causing hydronephrosis (key finding).
- Does NOT typically displace the aorta/IVC anteriorly (unlike lymphoma).
Question 5: Bladder Diverticulum (Acquired)
Stem: A 75-year-old man with a long history of benign prostatic hyperplasia (BPH) and voiding difficulties undergoes a CT urogram. The scan shows marked trabeculation of the bladder wall and multiple, wide-mouthed outpouchings (diverticula) arising from the bladder, particularly near the ureteric orifices.
Question: These diverticula are most likely:
(A) Congenital diverticula. (B) Acquired (pulsion) diverticula due to chronic bladder outlet obstruction. (C) Urachal remnants. (D) Fistulae to the bowel. (E) Transitional cell carcinoma.
Correct Answer: (B) Acquired (pulsion) diverticula due to chronic bladder outlet obstruction.
Explanation:
- Why (B) is correct: Acquired bladder diverticula are common in older men with chronic bladder outlet obstruction (BOO), most often from BPH. The increased intravesical pressure causes herniation of the bladder mucosa through weakened areas of the detrusor muscle. They are typically multiple, wide-mouthed, and seen alongside other signs of BOO like bladder wall trabeculation.
- Why (A) is wrong: Congenital diverticula are rare, usually solitary, and located near the ureteric orifice (Hutch diverticulum).
- Why (C) is wrong: Urachal remnants are midline structures extending towards the umbilicus.
- Why (D) is wrong: Fistulae are abnormal connections, not outpouchings.
- Why (E) is wrong: TCC is a solid tumour or wall thickening, not a diverticulum (though TCC can arise within a chronic diverticulum due to stasis).
Key Points: Bladder Diverticula
- Acquired (Pulsion):
- Cause: Chronic bladder outlet obstruction (e.g., BPH, urethral stricture).
- Appearance: Multiple, wide-mouthed; associated with bladder wall trabeculation.
- Complications: Stasis -> Infection, Stone formation, TCC.
- Congenital: Rare, solitary, near ureteric orifice (Hutch diverticulum), associated with reflux.
Question 6: Bladder Carcinoma (TCC/UCC)
Stem: A 68-year-old smoker presents with painless haematuria. A CT urogram is performed. The images show a 3 cm, irregular, papillary (frond-like) soft-tissue mass arising from the right lateral wall of the bladder, projecting into the lumen. There is associated focal thickening and enhancement of the adjacent bladder wall.
Question: What is the most likely diagnosis?
(A) Bladder Calculus (B) Blood Clot (C) Transitional Cell Carcinoma (TCC/UCC) (D) Prostate Cancer invading the bladder (E) Bladder Diverticulum
Correct Answer: (C) Transitional Cell Carcinoma (TCC/UCC).
Explanation:
- Why (C) is correct: TCC (Urothelial Carcinoma) is the most common malignancy of the bladder (>90%). It typically arises from the lateral walls or trigone. The most common appearance is a papillary, frond-like mass, although it can also be sessile or infiltrative. Focal wall thickening suggests muscle invasion.
- Why (A) is wrong: A calculus would be hyperdense and mobile (unless stuck in a diverticulum).
- Why (B) is wrong: A blood clot would be mobile, non-enhancing, and should resolve.
- Why (D) is wrong: Prostate cancer typically invades the bladder base near the trigone and would be associated with an enlarged, irregular prostate.
- Why (E) is wrong: A diverticulum is an outpouching, not an intraluminal mass.
Key Points: Bladder TCC/UCC
- Most common bladder malignancy.
- Risk Factors: Smoking, aniline dyes.
- Location: Lateral walls, trigone.
- Imaging (CT Urogram / MRI):
- Papillary mass (most common).
- Sessile mass or focal wall thickening.
- Enhances avidly.
- Staging: MRI is best for assessing depth of muscle invasion (T-stage). CT is used for nodal/distant mets (N/M-stage).
Question 7: Emphysematous Cystitis
Stem: An elderly diabetic woman presents with confusion, fever, and pneumaturia (passing air in urine). A CT scan shows gas locules circumferentially dissecting within the bladder wall. Gas is also seen within the bladder lumen.
Question: What is the diagnosis?
(A) Emphysematous Pyelonephritis (B) Emphysematous Cystitis (C) Vesico-enteric Fistula (D) Iatrogenic (post-catheterisation) (E) Bladder Calculi
Correct Answer: (B) Emphysematous Cystitis.
Explanation:
- Why (B) is correct: The presence of gas within the bladder wall is the defining feature of emphysematous cystitis, a rare but serious infection caused by gas-forming organisms (usually E. coli) in susceptible patients (typically diabetics).
- Why (A) is wrong: This involves gas in the kidney parenchyma.
- Why (C) is wrong: A fistula (e.g., colo-vesical from diverticulitis) causes gas in the bladder lumen (pneumaturia), but not gas within the wall itself.
- Why (D) is wrong: Instrumentation can introduce gas into the lumen, but not into the wall.
- Why (E) is wrong: Calculi are stones, not gas.
Key Points: Emphysematous Cystitis
- Definition: A rare, severe infection of the bladder wall with gas formation.
- Risk Factors: Diabetes Mellitus, immunocompromise, chronic UTIs, bladder outlet obstruction.
- Pathogen: Gas-forming organisms (e.g., E. coli, Klebsiella).
- CT Finding (Pathognomonic): Gas within the bladder wall. May also have gas in the lumen.
Question 8: Urachal Carcinoma
Stem: A 55-year-old man presents with haematuria. A CT scan reveals a large, heterogeneous, partially calcified soft-tissue mass arising from the anterior wall and dome of the bladder, in the midline, extending superiorly towards the umbilicus.
Question: Given the specific location, what is the most likely diagnosis?
(A) Transitional Cell Carcinoma (TCC/UCC) (B) Urachal Adenocarcinoma (C) Prostate Cancer invasion (D) Bladder Diverticulum with tumour (E) Squamous Cell Carcinoma
Correct Answer: (B) Urachal Adenocarcinoma.
Explanation:
- Why (B) is correct: The urachus is an embryological remnant connecting the bladder dome to the umbilicus. Carcinomas arising from this remnant are rare but typically occur in the midline, at the bladder dome or anterior wall. They are almost always adenocarcinomas (unlike most bladder cancers which are TCC) and often contain calcifications.
- Why (A) is wrong: TCC is much more common but typically arises from the lateral walls or trigone, is papillary, and rarely calcifies.
- Why (C) is wrong: Prostate cancer invades the bladder base, not the dome.
- Why (D) is wrong: A diverticulum is an outpouching; a tumour arising within one wouldn’t typically have this midline, superior extension.
- Why (E) is wrong: Squamous cell carcinoma of the bladder is rare and associated with chronic irritation (stones, Schistosomiasis), not the urachus.
Key Points: Urachal Carcinoma
- Definition: Rare malignancy arising from a urachal remnant.
- Location: Midline, anterior wall or dome of the bladder.
- Histology: Usually Adenocarcinoma.
- Imaging: Soft-tissue mass, often with calcifications. May extend towards the umbilicus.
Question 9: Vesicoureteric Reflux (VUR)
Stem: A 4-year-old girl with recurrent UTIs undergoes a Voiding Cystourethrogram (VCUG). During voiding, contrast is seen refluxing from the bladder up the right ureter and filling a dilated renal pelvis and calyces. The calyceal fornices appear blunted.
Question: According to the International Reflux Study grading system, what is the minimum grade of reflux demonstrated?
(A) Grade I (B) Grade II (C) Grade III (D) Grade IV (E) Grade V
Correct Answer: (D) Grade IV.
Explanation:
- Why (D) is correct: Grade IV VUR is defined as reflux reaching the renal pelvis with gross dilatation of the ureter, pelvis, and calyces, and blunting of the calyceal fornices.
- Why (A) is wrong: Grade I is reflux into the ureter only.
- Why (B) is wrong: Grade II is reflux into a non-dilated renal pelvis.
- Why (C) is wrong: Grade III is reflux into a mildly dilated renal pelvis/calyces with sharp fornices. The presence of gross dilatation and blunting makes it at least Grade IV.
- Why (E) is wrong: Grade V involves severe tortuosity of the ureter and loss of papillary impressions, which is more severe than described.
Key Points: VUR Grading (VCUG)
- Grade I: Ureter only.
- Grade II: Ureter + Pelvis (non-dilated).
- Grade III: Ureter + Pelvis (mild/moderate dilatation, sharp fornices).
- Grade IV: Gross dilatation, blunted fornices.
- Grade V: Gross dilatation, tortuous ureter, loss of papillary impressions.
Question 10: Posterior Urethral Valves (PUV)
Stem: A male neonate presents with a poor urinary stream and palpable flank masses. A Voiding Cystourethrogram (VCUG) demonstrates a markedly dilated and elongated posterior urethra, proximal to thin, sail-like membranes. The bladder is trabeculated, and there is bilateral severe vesicoureteric reflux (VUR).
Question: What is the most likely diagnosis?
(A) Posterior Urethral Valves (PUV) (B) Ureterocele (C) Prune Belly Syndrome (D) Neurogenic Bladder (E) Urethral Stricture
Correct Answer: (A) Posterior Urethral Valves (PUV).
Explanation:
- Why (A) is correct: This is the classic VCUG appearance of PUV, the most common cause of congenital bladder outlet obstruction in males. The key finding is the dilated posterior urethra proximal to the obstructing valves (membranes). Secondary signs include bladder trabeculation, diverticula, and VUR (due to the high pressures).
- Why (B) is wrong: A ureterocele is a cystic dilatation of the distal ureter within the bladder.
- Why (C) is wrong: Prune Belly Syndrome involves absent abdominal muscles, cryptorchidism, and urinary tract anomalies (dilated ureters, VUR), but not valves.
- Why (D) is wrong: Neurogenic bladder has abnormal function but no anatomical valves.
- Why (E) is wrong: A urethral stricture is an acquired narrowing, typically more distal, and not seen in neonates.
Key Points: Posterior Urethral Valves (PUV)
- Most common cause of congenital bladder outlet obstruction in males.
- VCUG Findings (Pathognomonic):
- Dilated, elongated posterior urethra.
- Abrupt calibre change at the level of the valves (membranes).
- Secondary Findings: Trabeculated bladder, diverticula, vesicoureteric reflux (VUR), bilateral hydroureteronephrosis.
Question 11: Ureteric Injury (Iatrogenic)
Stem: A 50-year-old woman develops flank pain and fever 3 days after a hysterectomy. A CT urogram is performed. The delayed excretory phase images show contrast accumulating in the left side of the pelvis, outside the expected course of the ureter. The left ureter proximal to this collection is dilated.
Question: What is the most likely diagnosis?
(A) Pelvic Abscess (B) Lymphocele (C) Ureteric Injury with urinoma formation (D) Vesicovaginal Fistula (E) Ovarian Vein Thrombosis
Correct Answer: (C) Ureteric Injury with urinoma formation.
Explanation:
- Why (C) is correct: Iatrogenic ureteric injury is a known complication of pelvic surgery (especially hysterectomy). The key finding on a delayed-phase CTU is extravasation of urine/contrast outside the collecting system, often forming a collection (urinoma). Proximal hydroureteronephrosis is expected.
- Why (A) is wrong: An abscess is an infected collection and would typically have a thick, enhancing rim; it would not opacify with excreted contrast.
- Why (B) is wrong: A lymphocele is a collection of lymphatic fluid (water density) and does not opacify.
- Why (D) is wrong: A vesicovaginal fistula is a connection between the bladder and vagina; contrast would leak into the vagina, not form a pelvic collection around the ureter.
- Why (E) is wrong: This is a venous thrombosis, not a fluid collection.
Key Points: Ureteric Injury
- Causes: Iatrogenic (gynaecological/colorectal surgery), penetrating trauma, calculi.
- Imaging (CT Urogram – Delayed Phase):
- Extravasation of contrast from the ureter.
- Formation of a fluid collection (urinoma).
- Proximal hydroureteronephrosis.
Question 12: Bladder Rupture (Extraperitoneal)
Stem: A 35-year-old man sustains a pelvic fracture in a road traffic accident. A CT cystogram is performed by retrograde filling of the bladder with contrast via a Foley catheter. The images demonstrate contrast extending into the prevesical space (Space of Retzius) and tracking along the fascial planes around the bladder, but not outlining bowel loops or extending into the paracolic gutters.
Question: This pattern is diagnostic of:
(A) Intraperitoneal Bladder Rupture (B) Extraperitoneal Bladder Rupture (C) Urethral Injury (D) Simple Bladder Contusion (E) Combined Intra- and Extraperitoneal Rupture
Correct Answer: (B) Extraperitoneal Bladder Rupture.
Explanation:
- Why (B) is correct: Extraperitoneal rupture is the most common type of bladder rupture (80-90%) and is strongly associated with pelvic fractures. The extravasated contrast/urine is confined to the extraperitoneal pelvic spaces, such as the Space of Retzius (prevesical space). A characteristic “molar tooth” appearance can be seen as contrast tracks along fascial planes.
- Why (A) is wrong: Intraperitoneal rupture typically occurs from a blow to a full bladder (less often associated with pelvic fracture). The contrast/urine leaks freely into the peritoneal cavity, outlining bowel loops and extending into the paracolic gutters.
- Why (C) is wrong: Urethral injury would show contrast extravasation below the bladder, around the urethra itself.
- Why (D) is wrong: A contusion involves no rupture or extravasation.
- Why (E) is wrong: While combined can occur, the description fits a purely extraperitoneal pattern.
Key Points: Bladder Trauma (CT Cystogram)
- Extraperitoneal Rupture (Common, Assoc. w/ Pelvic Fx):
- Contrast confined to extraperitoneal spaces (e.g., Space of Retzius).
- “Molar tooth” sign.
- Intraperitoneal Rupture (Less common, Blow to full bladder):
- Contrast free in peritoneum, outlining bowel loops, in paracolic gutters.
- Combined: Features of both.
Question 13: Ureterocele
Stem: An infant undergoes an ultrasound for antenatal hydronephrosis. The ultrasound demonstrates a duplex collecting system on the left. A thin-walled, cystic structure is seen prolapsing into the bladder lumen at the expected insertion site of the upper pole moiety ureter.
Question: What is this cystic structure?
(A) Bladder Diverticulum (B) Ureterocele (C) Urachal Cyst (D) Posterior Urethral Valve (E) Ectopic Ureter insertion
Correct Answer: (B) Ureterocele.
Explanation:
- Why (B) is correct: A ureterocele is a congenital cystic dilatation of the terminal intravesical (submucosal) segment of the ureter. It appears as a thin-walled cyst projecting into the bladder lumen. Ureteroceles are strongly associated with duplex collecting systems, typically arising from the upper pole moiety, which often inserts ectopically and obstructs.
- Why (A) is wrong: A diverticulum is an outpouching of the bladder wall itself.
- Why (C) is wrong: A urachal cyst is a midline structure between the bladder dome and umbilicus.
- Why (D) is wrong: PUV is an obstruction in the male urethra, not a cystic structure in the bladder.
- Why (E) is wrong: An ectopic ureter inserts somewhere other than the normal trigone, but it is not typically cystic unless it forms a ureterocele at its insertion.
Key Points: Ureterocele
- Definition: Congenital cystic dilatation of the intravesical ureter.
- Appearance: Thin-walled cyst projecting into the bladder lumen (“cobra head” sign on IVU).
- Association: Strongly associated with duplex collecting systems (usually obstructs the upper pole moiety).
- Complications: Obstruction, VUR (into lower pole), stone formation.
Question 14: Urethral Stricture
Stem: A 50-year-old man presents with a progressively weakening urinary stream and incomplete bladder emptying. He has a history of prior urethral instrumentation. A retrograde urethrogram (RUG) is performed.
Question: What is the most common cause of urethral strictures in men?
(A) Congenital anomalies (B) Straddle injury trauma (C) Infection (gonococcal urethritis) (D) Iatrogenic (instrumentation/catheterisation) (E) Pelvic fracture associated urethral injury
Correct Answer: (D) Iatrogenic (instrumentation/catheterisation).
Explanation:
- Why (D) is correct: In developed countries, the most common cause of urethral strictures is iatrogenic trauma from procedures like transurethral resection of the prostate (TURP), difficult catheterisation, or cystoscopy. These typically cause strictures in the bulbar or membranous urethra.
- Why (A) is wrong: Congenital strictures are rare.
- Why (B) is wrong: Straddle injuries classically injure the bulbar urethra but are less common overall than iatrogenic causes.
- Why (C) is wrong: Infection (historically gonorrhoea) was a common cause but is less so now with effective antibiotics. It typically causes long, irregular strictures.
- Why (E) is wrong: Pelvic fractures cause injury to the posterior (membranous/prostatic) urethra, which is a specific type, but less common overall than iatrogenic strictures.
Key Points: Urethral Strictures
- Definition: Fibrotic narrowing of the urethra.
- Most Common Cause: Iatrogenic (instrumentation).
- Other Causes: Trauma (straddle injury, pelvic fracture), Infection (gonorrhoea).
- Imaging: Retrograde Urethrogram (RUG) is the primary study to define the location, length, and calibre of the stricture. A VCUG assesses the posterior urethra.
Question 15: Transitional Cell Carcinoma (TCC) – Bladder Diverticulum
Stem: An 80-year-old man with a known large, chronic bladder diverticulum (secondary to BPH) presents with haematuria. A CT urogram shows the diverticulum, but now arising from its wall is an irregular, enhancing soft-tissue mass.
Question: Patients with chronic bladder diverticula are at increased risk of developing which type of malignancy within the diverticulum?
(A) Transitional Cell Carcinoma (TCC/UCC) (B) Squamous Cell Carcinoma (SCC) (C) Adenocarcinoma (D) Lymphoma (E) Sarcoma
Correct Answer: (A) Transitional Cell Carcinoma (TCC/UCC).
Explanation:
- Why (A) is correct: While SCC and Adenocarcinoma risk is slightly increased due to chronic stasis/inflammation within a diverticulum, TCC remains the most common histological type of cancer found within a bladder diverticulum, just as it is in the rest of the bladder. The chronic stasis is thought to increase contact time with urinary carcinogens.
- Why (B) is wrong: SCC is associated with chronic irritation (e.g., stones, Schistosomiasis, long-term catheters) and is less common than TCC in diverticula.
- Why (C) is wrong: Adenocarcinoma is rare in the bladder, typically associated with the urachus or chronic infection/exstrophy.
- Why (D) & (E) are wrong: Lymphoma and sarcoma of the bladder are very rare.
Key Points: Bladder Diverticula Complications
- Urinary Stasis within the diverticulum leads to:
- Infection.
- Stone Formation.
- Increased risk of Malignancy (most commonly TCC, but also SCC/Adeno).
- Imaging: Look for filling defects or irregular wall thickening within the diverticulum on CTU/MRI.
