Genito-urinary Flashcards
A 50-year-old man attends his GP feeling generally lethargic. The GP organizes blood tests
and these reveal renal impairment. A subsequent ultrasound examination shows bilateral
hydronephrosis without obvious cause. A CT scan of the abdomen then demonstrates that the
hydronephrosis is secondary to bilateral ureteric obstruction from abnormal retroperitoneal soft
tissue, intimately related to the aorta and IVC. Which of the following features on CT would
suggest that the soft tissue is more likely due to retroperitoneal fibrosis, rather than a malignant
cause? [B1 Q38]
A. Nodular contour to the soft tissue.
B. Contrast enhancement of the soft tissue.
C. More severe hydronephrosis in the kidneys.
D. Close application of the soft tissue to the adjacent vertebrae.
E. Soft-tissue extension above and below the level of the renal hila.
Close application of the soft tissue to the adjacent vertebrae.
Unfortunately attempts to consistently distinguish benign retroperitoneal fibrosis (RPF) from
malignancy are fraught with danger, but there are certain CT findings which are more
commonly seen in one or other of these conditions.
Malignancy tends to be larger and bulkier, displaying mass effect and displacing the aorta and IVC anteriorly from the spine and the ureters laterally. The purely fibrotic process of benign RPF tends to tether these structures to the adjacent vertebrae
Malignancy is more likely to extend cephalad to the renal hila, with benign RPF remaining
caudal to the hila. Neoplasia also more typically has a nodular outline, whereas benign RPF
usually manifests as a plaque-like density. There are, of course, exceptions to both these
features.
Contrast enhancement is not a reliable feature for distinguishing benign RPF from malignancy,
as both malignancy and active RPF can enhance with contrast. Similarly, the degree of
hydronephrosis caused is not a good distinguisher.*
Regarding retroperitoneal fibrosis (RPF): [B3 Q 42]
A. Is common in females in the primary form
B. Beta-blockers are a common cause
C. Desmoplastic response to malignancy is the most common case in secondary RPF
D. Causes lateral deviation of the mid ureter
E. In the primary form responds to steroids
E
Two thirds of cases of RPF are primary and one third are secondary. Both forms are more
common in males. Secondary causes include drugs such as methysergide, beta-blockers,
phenacetin. Medial deviation of the ureter occurs in the mid third.
A 60-year-old male, treated long term for hypertension with hydralazine, develops bilateral
hydronephrosis. On CT KUB, the ureters are deviated medially and obstructed by a large,
plaque-like, para-aortic, soft-tissue density. The aorta appears ‘taped-down’ to the vertebral
column rather than elevated by the para-aortic tissue. Which of the following is the most likely
diagnosis? [B4 Q14]
a. enlarged retroperitoneal lymph nodes due to Hodgkin’s disease
b. enlarged retroperitoneal lymph nodes due to non-Hodgkin’s lymphoma
c. retroperitoneal fibrosis
d. bilateral ureteral transitional cell carcinoma
e. metastatic lymph node enlargement from testicular embryonal cell carcinoma
Retroperitoneal fibrosis
Retroperitoneal fibrosis can cause extrinsic compression of both ureters and retroperitoneal
vascular structures such as the aorta, inferior vena cava and iliac vessels. It can be idiopathic
or secondary to inflammatory aortic aneurysm, retroperitoneal metastases, haemorrhage,
abscess, urinoma, diverticulitis, appendicitis, Crohn’s disease, and drugs such as ergot
alkaloids and hydralazine.
Malignant retroperitoneal lymphadenopathy causing ureteric obstruction tends to encircle
the aorta, elevating it off the vertebral column. In contrast, retroperitoneal fibrosis rarely
extends between the aorta and the vertebrae, and therefore appears to tape the aorta down
to the spine.
A 65-year-old man with known abdominal aortic aneurysm and under follow up for lymphoma,
presents with backache. Contrast-enhanced CT shows a doughnut shaped soft tissue mass
surrounding the lower part of aneurysmal abdominal aorta and the ureters are pulled medially
with bilateral hydronephrosis. What is the most likely diagnosis? [B5 Q21]
(a) Retroperitoneal fibrosis
(b) Lymphoma recurrence
(c) Aneurysm leak
(d) Radiation injury
(e) None of the above
Retroperitoneal fibrosis
This is hard fibrous tissue enveloping the retroperitoneum, including the great vessels, ureters
and the lymphatics. The plaque typically begins around the aortic bifurcation and extends
cephalad to the renal hilum, and it rarely extends below the pelvic brim.
A 28-year-old woman suffers blunt injury to her abdomen following a road traffic accident. A
polytrauma CT scan does not demonstrate any intra-abdominal injuries, but there are features indicating retroperitoneal injuries. Regarding these features, which of the following is true?
[B2 Q18]
a. Retroperitoneal air may indicate pulmonary injuries
b. Haematomas in the posterior pararenal space do not extend into the pelvis
c. The most common region demonstrating retroperitoneal haemorrhage following trauma is
usually around the aorto-caval region in the midline
d. Adrenal injuries are more common on the left
e. Low-attenuation fluid (<20HU) in the retroperitoneum is always indicative of injury to the
pelvi-calyceal system or the ureters
Retroperitoneal air may indicate pulmonary injuries
-
Air in the retroperitoneum can follow pneumothorax. However, in the absence of
pneumothorax, it is strongly indicative of duodenal/colonic injury. -
The posterior and anterior pararenal spaces communicate freely with the pelvic
retroperitoneum, whilst the perinephric space is enclosed. - The retroperitoneum is divided into three zones: I – midline retroperitoneum; II – lateral
retroperitoneum; and III – pelvic retroperitoneum. Zone III is the commonest site for
haematoma following blunt injury. - Adrenal injuries are more common on the right.
- Low-attenuation fluid can be seen even in the absence of urine leak, usually indicating
hypoperfusion shock syndrome.
A 60-year-old female presents with a large abdominal mass. CT demonstrates a large
retroperitoneal fat-containing mass. Which of the following is true about the different fat-
containing retroperitoneal masses? [B2 Q28]
a. Predominantly low signal on T1-weighted and a high signal on T2-weighted images preclude
a diagnosis of liposarcoma
b. Calcification within a liposarcoma is usually associated with a better prognosis
c. Lipomas are rare in the retroperitoneum
d. An extremely FDG-avid retroperitoneal fat-containing tumour is almost certainly a
liposarcoma
e. Given time, most lipomas will dedifferentiate into liposarcomas
Lipomas are rare in the retroperitoneum
Liposarcomas are the most common sarcomas in the retroperitoneum. Whilst well differentiated liposarcomas are the commonest, myxomatous and dedifferentiated liposarcomas can have varying appearances and so low T1-weighted signal does not preclude a diagnosis of liposarcoma.
Lipomas, whilst exceedingly rare in the retroperitoneum, almost undergo malignant changes. Whilst liposarcomas can have minimal-to-increased FDG uptake, a very FDG-avid fat-containing retroperitoneal tumour is quite likely a hibernoma.
A 58-year-old smoker presents with haemoptysis and chest pain. A CT of chest confirms a lung
carcinoma. While reporting the CT you notice that there is enlargement of the right adrenal
gland. The patient has already left the department, but by chance is due to have an MRI scan
of lumbar spine at a nearby institution the following morning. Due to time constraints, they can
only fit in one sequence to image the adrenal glands. Which one sequence is of most use in
further characterizing the adrenal abnormalities? [B1 Q35]
A. T2WI.
B. STIR.
C. Axial T1WI with fat saturation.
D. In- and out-of-phase T1WI.
E. DWI.
In- and out-of-phase T1WI.
This is a T1WI technique and will reveal the presence of intracellular lipid (microscopic fat) via a dropout of
signal on the out-of-phase imaging when compared to the in-phase imaging. Thus, a benign
adrenal adenoma will show such signal dropout (20% or greater in quantity is diagnostic; 10–
20% is highly suggestive), whilst adrenal metastases will not.
However, approximately 15% of benign adenomas do not accumulate intracellular lipid and
may retain signal on the out-of-phase imaging; in such cases, dynamic gadolinium-enhanced
images can increase specificity to over 90–95% (by showing washout characteristics as seen
on CT).
If there is still doubt, PET-CT is useful. Adrenal hyperplasia may also show loss of signal on the
out-of-phase imaging. Of note an adrenal cortical carcinoma can show dropout of signal in
portions on the out-of-phase sequence, but there is not the uniform loss of signal as seen
with adenomas.
The T1WI with fat saturation will show signal dropout in areas of extracellular lipid, e.g.
macroscopic fat in lipomas, dermoid cysts, or the subcutaneous tissues. T2WI is not of much
benefit in distinguishing benign from malignant adrenal masses unless the tumour is a
phaeochromocytoma, which can show very high T2WI signal.
A 64-year-old patient is referred for a CT of abdomen 10 days post laparotomy for a right
hemicolectomy for colonic adenocarcinoma. His post-operative course is initially uneventful,
but the request form states that over the last 2 days he has developed pyrexia and today his
inflammatory markers are markedly raised, he is ‘septic’ and unwell. The surgeons suspect a
perforation or anastomotic leak, but you find no significant free fluid or air. There is marked
bilateral enhancement of the adrenal glands, which are normal in size. The remainder of the
abdominal viscera are unremarkable and the IVC and aorta are normal in calibre. There is
marked consolidation at both lung bases. What is the significance of the appearance of the
adrenal glands? [B1 Q46]
A. Hypovolaemic shock.
B. Phaeochromocytoma.
C. Hypervascular metastases.
D. Addisonian crisis secondary to tuberculous adrenalitis.
E. Adrenal hyperplasia as a response to the recent surgery
Hypovolaemic shock.
Marked adrenal enhancement may be the only sign of significant hypovolaemic shock. This is
thought to be due to hyper-perfusion of the adrenal glands because of their crucial role in
this clinical situation. Other signs that may accompany this sign, the ‘hypoperfusion complex’
described in shock due to trauma, are collapsed IVC, small hypodense spleen, small aorta and
mesenteric arteries, shock nephogram (lack of renal contrast excretion), intense pancreatic
enhancement, dilatation of fluid-filled intestine with thickening of folds, and increased
enhancement of the wall. However, in cases of hypovolaemic shock due to sepsis, where
there has been rapid fluid replacement, the IVC and aorta may be of normal calibre and
persisting marked adrenal enhancement has been described as the only abnormality.
Phaeochromocytomas are bilateral in only approximately 10% and this would be even less
likely in the presence of another neoplasm. Hyper-vascular metastases are uncommon in
colonic carcinoma. Adrenal hyperplasia may occur as a response to stress, but the adrenals
would enhance normally. In tuberculous adrenalitis, the adrenal glands show areas of
necrosis and sometimes calcification, with possible rim enhancement. In all four of these
alternative options, the adrenal glands would be enlarged.
A 2 cm adrenal lesion with an attenuation value of 20 HU is seen on a non-contrast CT of a
patient with lung cancer. The following are all true except: [B2 Q40]
a. A 60% washout on delayed post-contrast CT would be in keeping with an adenoma
b. A signal intensity decrease of 40% or more on chemical shift imaging indicates malignancy
c. PET-CT is interpreted as positive if the FDG uptake of the adrenal lesion is greater than that
of the liver
d. Functioning adrenal adenomas can be a cause for false positives on PET-CT
e. PET-CT has somewhat higher and more consistent accuracy than dynamic CT or chemical
shift MR imaging.
A signal intensity decreases of 40% or more on chemical shift imaging indicates malignancy
A signal intensity decreases of less than 20% is usually indicative of malignancy in an adrenal
lesion.
A 54-year-old female patient presents with anaemia and haematuria. A CT of abdomen
confirms renal cell carcinoma of the right kidney, but there is also enlargement of the right
adrenal gland. Which of the following CT characteristics is most consistent with a benign
adrenal adenoma? [B1 Q41]
A. A pre-contrast attenuation of 50.
B. An immediate post-contrast attenuation of 50.
C. A relative percentage washout (RPW) of 60%.
D. Lesion size of 50 mm.
E. Heterogeneity of the lesion.
A relative percentage washout (RPW) of 60%.
- Findings consistent with an adrenal adenoma are:
- a pre-contrast attenuation of 10 HU or less,
- an absolute percentage washout (APW) of 60% or greater, or
- an RPW of 40% or greater.
The percentage washout is calculated by comparing the attenuation value at 15 minutes post
contrast (delayed H), to the value in the portal venous phase (enhanced H), and in the case of
APW, the pre-contrast value.
RPW = 100 × (enhanced H – delayed H)/ (enhanced H)
APW = 100 × (enhanced H – delayed H)/ (enhanced H – pre-contrast H)
In practice, an unenhanced scan is not usually performed and thus only the RPW is calculated.
Adrenal cortical carcinomas usually have an RPW of less than 40% although exceptions have
been reported. Their large size (usually greater than 6 cm), heterogeneity pre-contrast
(necrosis), and heterogeneous enhancement are more reliable indicators of the diagnosis.
Phaeochromocytomas and hyper-vascular metastases may mimic adenomas, but most
metastases show RPW < 40% and APW < 60%.
A man is found to have a single adrenal mass of diameter 35 mm. On an unenhanced CT scan,
the average attenuation value is 30 HU. On a CT timed at 60 seconds after iodinated contrast
medium injection, the attenuation value of the mass is 90 HU. By 15 minutes after contrast, the
attenuation value is 50 HU. Which of the following is the most likely diagnosis? [B4 Q37]
a. lipid-rich adenoma
b. lipid-poor adenoma
c. metastasis
d. adrenal cortical cancer
e. adrenal haemorrhage
Lipid poor adenoma
An unenhanced CT attenuation value of less than 10 HU is in keeping with a lipid-rich
adenoma. With a threshold of 60% or higher for absolute contrast-enhancement washout, a
sensitivity of 98% and specificity of 92% can be achieved in differentiating adenomas from
non-adenomas. Percentage of enhancement washout ¼ ([attenuation at 60 s – attenuation
at 15min] / [attenuation at 60 s – attenuation on plain CT]) x 100. Applying this to the figures
quoted in the question gives an absolute washout of around 66.6%.
A 70-year-old, who is a lifelong smoker, is investigated for weight loss. Among other findings,
an adrenal nodule of 3 cm short axis diameter is found on post-contrast CT, with an average
attenuation value of 60 HU. On in-phase T1W images, the adrenal nodule is isointense to spleen;
on out-of-phase T1W images, the whole of the nodule returns significantly lower signal than
the spleen. Of the following, which is the most likely diagnosis for this adrenal nodule? [B4
Q75]
a. lung cancer metastasis
b. collision tumour
c. adrenal adenoma
d. phaeochromocytoma
e. hyperfunctioning adrenal cortical neoplasm
Adrenal adenoma
Signal dropout during out-of-phase T1W sequences occurs in lipid-rich adenomas by virtue of
their fat content. Adrenal primaries and metastases do not share this feature. Collision
tumours arise when a metastasis occurs in an adrenal gland that already contains an adenoma,
in which case signal characteristics of both are seen on the T1W in- and out-of-phase
sequences
A 52-year-old male smoker has been recently diagnosed with bronchogenic carcinoma with
cerebral metastasis. Staging CT shows a 1.5 cm nodule in the left adrenal gland. On MRI, the
nodule is isointense to spleen on T2 and shows marked hypo-intensity on out-of-phase GRE
images. What is the most likely diagnosis? [B5 Q16]
(a) Adrenal metastasis
(b) Adrenal adenoma
(c) Adrenocortical carcinoma
(d) Adrenocortical hyperplasia
(e) Adrenal cyst
Adrenal adenoma
This is the typical feature of adrenal adenoma and is seen in more than 95% adenomas. The
fat/lipid in the adenoma causes a chemical shift artefact which results in significant loss of
signal on out-of-phase GRE images.
A 45-year-old man presents with left-sided pain in abdomen. CT shows a 5 cm mass in the left
adrenal gland, predominantly containing tissues with Hounsfield units of approximately -80.
On MRI, the lesion high signal on T1 and low signal on STIR sequence. What is the most likely
diagnosis? [B5 Q32]
(a) Liposarcoma
(b) Adrenal myelolipoma
(c) Adrenal carcinoma
(d) Adrenal metastases
(e) Pheochromocytoma
Adrenal myelolipoma
Given the negative Hounsfield units on CT and loss of signal on fat suppression, the lesion
contains predominantly fat. These are benign tumours containing fat and haematopoietic
tissue. Presence of fat in an adrenal lesion is highly suggestive of a myelolipoma.
A 36-year-old male patient presents with abdominal pain. He has a history of hypertension and
obesity. A CT of abdomen reveals a 6-cm right adrenal mass, which shows heterogenous but
peripheral enhancement, necrosis, and some calcification. There is early invasion of the IVC.
The left adrenal gland is atrophied. What is the most likely diagnosis? [B1 Q30]
A. Neuroblastoma.
B. Adrenal cortical carcinoma.
C. Myelolipoma.
D. Adrenal adenoma.
E. Phaeochromocytoma
Adrenal cortical carcinoma.
The clinical picture is one of undiagnosed Cushing’s syndrome with obesity and hypertension.
In this case it is adrenocorticotropic hormone (ACTH) independent Cushing’s, as the negative
feedback from the cortisol producing adrenal carcinoma causes reduction in ACTH levels and
atrophy of the contra-lateral, normal adrenal gland.
Adrenal adenoma can cause Cushing’s syndrome, but the features described point to adrenal
carcinoma. They have a bimodal distribution (first and fourth decades). On average 55% are
functional, manifesting with Cushing’ syndrome, feminization, virilisation, or a mixture of
these. Hypertension is common in all syndrome types.
Most masses measure more than 6 cm. They are heterogenous on unenhanced CT, owing to
necrosis. They enhance heterogeneously, often peripherally, with a thin rim of enhancing
capsule in some cases. In 19–33% of cases calcification or microcalcifications have been
identified. The liver is the most common metastatic site, followed by the lung and lymph
nodes. Direct extension and tumour thrombus can also occur. Compression of the IVC can
lead to presentation with abdominal pain, lower extremity oedema or pulmonary embolism.
Neuroblastoma is a disease of childhood. Myelolipoma is a relatively uncommon benign
adrenal mass containing fat and haemopoietic tissue.
Phaeochromocytoma is classically brightly enhancing but can have a variety of CT
appearances. It would explain hypertension, but not atrophy of the contra-lateral adrenal
gland. Phaeochromocytoma rarely invades the IVC.
A 40-year-old female is found to have a suspected incidental left adrenal lesion on ultrasound.
Which of the following CT or MR features is least likely in a phaeochromocytoma? [B2 Q29]
a. High signal on T2-weighted images
b. Avid enhancement post-gadolinium injection
c. Mean lesion attenuation of more than 10HU
d. Less than 40% washout on delayed CT scanning
e. Calcification
Calcification
Whilst phaeochromocytomas can have varied appearances on CT and MR, typically they are
high on T2-weighted and low on T1-weighted images and enhance avidly post-contrast. They
normally have an attenuation value of more than 10 HU, but calcification is seen in only about
10% of cases.
A middle-aged woman presenting to the medical team with headaches, palpitations,
tachycardia, and hypertension is suspected to have a phaeochromocytoma. You are asked
advice on imaging modalities. Which one of the following statements is true regarding the
imaging characteristics of a phaeochromocytoma? [B2 Q36]
a. I-131 MIBG imaging is only 20% sensitive for phaeochromocytoma
b. Poor contrast enhancement on CT
c. Bilateral in 25% of cases
d. Usually hypovascular on angiography
e. No change in signal intensity between in-phase and out-of-phase T1-weighted MRI images
No change in signal intensity between in-phase and out-of-phase T1-weighted MRI images
There is no change between the in-phase and out-of-phase imaging on MRI as there is very
low-fat content in phaeochromocytoma. MR is the method of choice for imaging and usually
(60%) the phaeochromocytoma will be hyperintense to spleen on T2-weighted imaging.
Angiography can localise the lesion in >90% of cases. Appearance on ultrasound can be
variable with about 70% appearing as solid lesions whilst 15% are cystic. The ‘rule of tens’
applies to phaeochromocytoma, i.e., 10% are bilateral, 10% are extra-adrenal, 10% are
malignant and 10% are familial.
A 50-year-old man has surgery to remove a tumour confined to the adrenal gland. Histology
reveals a phaeochromocytoma. Subsequently, he develops hypertension and urinary
vanillylmandelic acid is found to be elevated. An MIBG scan is performed. Activity in which
of the following organs is most likely to be a metastasis? [B4 Q31]
a. lung
b. bladder
c. thyroid
d. colon
e. spleen
Lung
Normal MIBG uptake is seen in myocardium, liver, spleen, bladder, adrenal glands, salivary
glands, nasopharynx, thyroid and colon. Abnormal MIBG activity is seen in
phaeochromocytoma (paraganglioma when extra-adrenal), neuroblastoma, carcinoid
tumour, medullary thyroid carcinoma and ganglioneuroma. Ten per cent of
phaeochromocytomas are familial, 10% bilateral or multiple, 10% extra-adrenal and 10%
malignant. Metastatic spread is to bone, lymph nodes, liver, and lung.
A 57-year-old hypertensive woman presents with recurrent abdominal pain. Urine shows
elevated levels of vanillylmandelic acid. CT shows a large mass at the superior pole of right
kidney. On MRI, the lesion is heterogenous, and appears low signal on T1 and high signal on
T2 with enhancement with gadolinium. What is the most likely diagnosis? [B5 Q27]
(a) Lymphoma
(b) Renal cell carcinoma
(c) Pheochromocytoma
(d) Retroperitoneal liposarcoma
(e) Nodal metastasis
Pheochromocytoma
This tumour usually arises from the adrenal medulla. Note the 10% rule: 10% are extra-
adrenal, 10% malignant and 10% bilateral. MRI features are typical and with elevated urine
vanillylmandelic acid levels it is diagnostic.
In a 72-year-old man undergoing abdominal CT for ongoing lower abdominal pain, a 2 cm
right-sided adrenal lesion is detected. He has no history of malignant disease. Which of the
following parameters would be more in keeping with a malignant than a benign adrenal lesion?
[B5 Q24]
a. Size of 2.5cm
b. Hounsfield units of 8 on non-enhanced CT
c. Washout of >60% when comparing non-enhanced CT with contrast-enhanced CT
d. Loss of signal within the lesion on out-of-phase MRI imaging
e. Maximum standardised uptake value >4 on FDG-PET
Maximum standardised uptake value >4 on FDG-PET
This is suspicious for metastatic malignant disease with the most common primary sites being
lung, colon, melanoma, and lymphoma. An incidental adrenal lesion is detected on 1% of
abdominal CT. Even in the presence of a known malignancy, 87% of incidental lesions less
than 3 cm in size are benign. Other features suggestive of malignancy are large size,
irregularity, and inhomogeneity.
In dynamic renal imaging: [B3 Q24]
A. The patient must not eat or drink for 6 hours prior to the test
B. Provides information on total and divided function only
C. Total divided renal function are evaluated in addition to rates of transit through parenchyma
and outflow track
D. Diethylene triamine Penta acetic acid (DTPA) has the advantage of higher renal
concentration than inulin
E. DTPA is excreted by glomerular filtration and tubular excretion
Total divided renal function is evaluated in addition to rates of transit through parenchyma and outflow track
This investigation requires a hydrated patient to lie supine with knees slightly flexed to reduce
lumbar lordosis. DTPA is handled the same way as inulin. D and E are correct for MAG3
A 35-year-old female has investigations for episodic right loin pain. Ultrasound scan of the
renal tract is unremarkable. A DMSA scan is performed with the patient sitting and shows only
30% contribution to the total tracer activity from the right kidney. When the counts are repeated
supine, the contribution from the right kidney is 50%. What is the most likely abnormality of
the right kidney? [B4 Q26]
a. nutcracker kidney
b. nephroptosis
c. pelviureteric junction obstruction
d. ureteric calculus
e. vesicoureteric reflux
Nephroptosis
Ptosis of the mobile kidney when erect can cause symptoms and underestimation of
parenchymal DMSA uptake. Since the differential function may be a factor in considering
removal of a kidney, the technique should account for the possibility of nephroptosis
influencing the counts. A nutcracker kidney is a rare cause of left-sided loin pain and
haematuria; it is caused by compression of the left renal vein between the aorta and superior
mesenteric artery.
A 65-year-old male being investigated for microscopic haematuria has an ultrasound scan,
which suggests a 20 mm tumour in the cortex of the interpolar region of the left kidney. CT
scan confirms an enhancing mass in the same location. On DMSA SPECT, this abnormality
has good uptake. Which of the following is the most appropriate management? [B4 Q30]
a. no further action
b. biopsy
c. nephrectomy
d. image-guided drainage
e. chemotherapy
No further action
The abnormality described is prominent or hypertrophic cortex since it takes up DMSA, which
in the kidneys is a parenchymal tracer. Renal cell carcinoma, cysts, abscess, haematoma, scar
and infarct would be seen as photopenic areas on DMSA SPECT, if large enough
A 73-year-old male diabetic patient, with poorly controlled hypertension, is referred for renal
Doppler ultrasound due to an episode of flash pulmonary oedema. He has a history of stage 3
chronic kidney disease. The ultrasound shows a small left kidney, which measures 5 cm in
bipolar diameter. The right kidney is also small, measuring 6 cm. The resistive indices measure
0.9 on both sides. The peak systolic velocity is 130 cm/s on the left and 150 cm/s on the right.
Which interventional treatment would be recommended for this patient? [B1 Q24]
A. Renal artery angioplasty on left side.
B. Renal artery stenting on left side.
C. Renal artery stenting on right side.
D. Bilateral renal artery stenting.
E. No intervention
No intervention.
The factors described are all indicators of poor outcome following renal artery intervention.
Reduced renal size bilaterally indicates advanced bilateral renal disease, unlikely to respond
to intervention. The renal ultrasound Doppler patterns are also not suggestive of renal artery
stenosis, which is indicated by a peak systolic velocity of greater than 180 cm/s. Resistive
indices of greater than 0.7 indicate a likelihood of improvement after intervention
You are the interventional radiology fellow in your hospital. A nephrologist has asked you for
an opinion on four patients they feel require renal arterial intervention.
Patient A is a 68-year-old male who has had a catheter angiogram which showed a 60%
narrowing in the right renal artery. This patient has refractory hypertension.
Patient B is a 42-year-old female, also with refractory hypertension. She has had an MR
angiogram, which has shown several stenoses, with intervening mild aneurysm formation, in
the proximal right renal artery.
Patient C is a 72-year-old female with impaired renal function, who underwent captopril renal
scintigraphy. On the baseline study, there was a similar appearance of the kidneys. On the
captopril study, there was a differential split of renal function of 15% between the right and
left kidney, with a decrease of time to peak activity of 320 seconds.
The final patient D had a renal Doppler ultrasound, which showed a biphasic flow pattern in
the segmental arteries, with a slow upstroke. Which of these patients has significant
atherosclerotic renal artery stenosis? [B1 Q29]
A. Patients A and B.
B. Patients C and D.
C. Patients A, C, and D.
D. Patients B, C, and D.
E. All of them.
Patients C and D
A 70% stenosis is taken as the cut-off for significant stenosis. Patient B is atypical in their age.
They also have imaging characteristics typical of fibromuscular dysplasia. Patients C and D
have classical imaging features of renal artery stenosis (RAS). Regarding ultrasound diagnosis
using Doppler, this is made by either showing flow acceleration immediately distal to the site
of stenosis or showing dampened flow in the segmental arteries. In the renal artery, a peak
systolic velocity of over 180 cm/s combined with a renal/aortic velocity ratio of over 3 is
reported as being the most sensitive method of detecting RAS.
You are consulted about a 24-year-old male patient who is day 3 following a blind right-sided
renal biopsy, which diagnosed glomerulonephritis. He has been well until today when he
developed acute right flank pain and haematuria. The urologists asked for an IVU prior to
assessing the patient. They feel this showed an absent kidney, but on the 15- and 20-minute
images, you feel you can detect a faint nephrogram that is slightly more pronounced on the 20-
minute image. Given your suspicions about the cause, which of the following would be the
least likely to contribute to the diagnosis? [B1 Q34]
A. Ultrasound.
B. MRI with GE sequences of the right kidney.
C. MRI with SE sequences of the right kidney.
D. Arterial phase CT abdomen.
E. Portal venous phase CT abdomen.
Arterial phase CT abdomen.
The IVU has surprisingly been helpful in showing a delayed increasing nephrogram, a classical,
although uncommon, appearance of renal vein thrombosis. This is also indicated by the
history of glomerulonephritis, which can manifest as nephrotic syndrome, the most common
cause for renal vein thrombosis.
Ultrasound is often successful at identifying a thrombosed right renal vein but is not useful in
assessing the longer left renal vein.
Gradient and SE sequences are both helpful in assessing the renal venous system, with GE
giving low-signal thrombus and SE giving high-signal thrombus.
Arterial phase CT would be too early to show a venous filling defect and thus may not
contribute, although it may show a rim nephrogram.
Portal venous phase CT is reasonably sensitive at detecting the lack of enhancement within
the renal vein and abnormal enhancement pattern within the affected kidney.
A 45-year-old male is diagnosed with renal cell carcinoma and is being worked up for curative
nephrectomy. Which one of the following imaging modalities would you advise as being the
most accurate at ruling out malignant renal vein invasion? [B2 Q19]
a. Doppler ultrasound
b. B-mode ultrasound
c. CT
d. MRI
e. PET-CT
MRI
MRI is superior to the other imaging modalities listed at ruling out renal vein invasion. CT is
still very accurate (reported as high as 96%), but MR has the advantage of being able to
accurately differentiate benign from malignant thrombus. MR offers no advantage in
detecting nodal disease, however, and patients being considered for curative surgery should
undergo staging CT of the chest, abdomen and pelvis. PET does not have a specific role for
detecting renal vein invasion.
A 32-year-old patient with a history of renal failure has undergone a renal transplant in your
centre. You are carrying out serial ultrasound investigations over the weekend to assess the
success of the transplant. The graft was a cadaveric transplant. The initial ultrasound scan
showed no evidence of peri-graft collection but did show mild renal pelvic dilatation. The
pulsatility index (PI) was 2.0 and the resistive index was 0.9. The patient was oliguric. Due to
the fears of acute rejection, the patient was commenced on cyclosporine and steroids. The
patient, now day 4, is currently anuric and has developed pain over the graft site. You have
done an ultrasound. The arterial flow in the kidney has changed. Proximally you notice reversal
of diastolic flow evident on spectral waveforms, but in other areas there is no flow evident in
the interlobar arteries. Flow is still present in the main renal artery. The RI is now 0.95 and the
PI is unchanged. There is still mild renal pelvic dilatation, but you notice a tubular structure of
intermediate echogenicity in the renal hilum. There is no evidence of peri-graft collection.
What do you think the most appropriate next investigative/ therapeutic step is? [B3 Q73]
A. Continue immunosuppression and further observation, with appropriate fluid administration.
B. Continue immunosuppression and renal biopsy.
C. Refer for immediate arterial intervention.
D. Refer for immediate venous intervention.
E. Nephrostomy.
Refer for immediate venous intervention.
There are several complications to be aware of in the immediate post-transplant period. The
most efficient and cost-effective method of surveillance for these is ultrasound.
Acute rejection and acute tubular necrosis (ATN) both occur early in the post-transplant phase
and can be difficult to differentiate. Both can cause elevation of pulsatility index (PI) (normal
<1.5) and resistive index (RI) (normal <0.7), although these tend to be higher with rejection.
ATN is more common with cadaveric transplants. It usually resolves within a matter of days
or weeks, but ultimately biopsy can be necessary to reliably differentiate these processes.
This patient probably had a degree of ATN initially.
Arterial occlusion is uncommon and is evident by reduced/absent arterial flow in the main
artery as well as in the interlobar arteries, which can demonstrate loss of flow with any cause
of severe oedema (e.g. renal vein thrombosis or acute rejection).
Renal vein thrombosis causes pain and anuria. It is associated with early treatment with
cyclosporine and steroids. It also causes a rise in the RI and PI. The key feature to notice is the
persistent flow in the main renal artery, reducing the likelihood of renal arterial thrombosis.
There is also a tubular structure noted in the hilum, which is what a thrombosed renal vein
looks like, and reversal of diastolic flow on arterial traces.
You are asked to assess a renal transplant kidney in the early post-operative period for any
abnormality and to serve as a baseline study. Which of the following findings on colour
Doppler ultrasound regarding the PI, RI, and B mode ultrasound imaging, regarding renal
morphology, would be considered within normal limits? [B1 Q74]
A. PI < 1.5, RI < 0.7, loss of cortico-medullary differentiation.
B. PI < 1.5, RI < 0.7, prominence of renal pyramids.
C. PI > 1.8, RI < 0.7, loss of cortico-medullary differentiation.
D. PI > 1.8, RI < 0.7, prominence of renal pyramids.
E. PI < 1.5, RI > 0.9, loss of cortico-medullary differentiation.
F. PI < 1.5, RI > 0.9, prominence of renal pyramids.
G. PI > 1.8, RI > 0.9, loss of cortico-medullary differentiation.
H. PI > 1.8, RI > 0.9, prominence of renal pyramids.
PI < 1.5, RI < 0.7, prominence of renal pyramids.
PI < 1.5 or RI < 0.7 can be regarded as normal, whilst a PI > 1.8 or RI = 0.9 should be regarded
as abnormal. Although both ATN and acute rejection cause the PI and RI to rise, the likelihood
of acute rejection is greater with higher values. Complete absence of diastolic flow, or flow
reversal, is due to acute rejection in most of the case.
Morphologically, the transplant kidney is very similar to the native and many of the subtle
differences are attributed to the improved resolution of the former. There is a well-defined
renal parenchyma peripherally, with a highly reflective echogenic sinus centrally. In
distinction to the native kidney, the renal pyramids are more commonly visualized within the
transplant, being hypoechoic, relative to the parenchyma itself.
Loss of cortico-medullary differentiation is pathological and is a B mode finding that can be
associated with acute rejection.
Which of the following causes immediate faint persistent nephrogram on Intravenous Urogram
(IVU)? [B3 Q13]
A. Renal vein thrombosis (RVT)
B. Acute obstruction
C. Acute hypotension
D. Acute tubular necrosis
E. Chronic obstruction
Renal Vein Thrombosis
Immediate faint persistent nephrogram
RVT
Acute glomerulonephritis
Chronic severe ischaemia
Which is the cause of rim nephrogram? [B3 Q14]
A. Acute complete arterial occlusion
B. Acute ureteric obstruction
C. Polycystic kidney disease
D. Medullary sponge kidney
E. Acute pyelonephritis
Acute complete arterial occlusion
Rim nephrogram
Acute complete arterial occlusion
Severe hydronephrosis
Striated nephrogram
Acute ureteric obstruction
Acute pyelonephritis
Acute renal vein thrombosis
AR polycystic kidney
Medullary sponge kindey
A 30-year-old man with known Hep B surface Antigen (HBsAg), abdominal pain, malaise and
weight loss is diagnosed with Polyarteritis nodosa (PAN). Which of the following is true? [B3
Q25]
A. Affects small arteries only
B. Causes aneurysms which are usually 5-10 mm in size
C. Produces moth-eaten nephrograms after thrombosis of the microaneurysms
D. Angiography has significantly higher sensitivity than specificity in diagnosis
E. Angiography has a much higher positive predictive value (PPV) compared with negative
predictive value (NPV)
Produces moth-eaten nephrograms after thrombosis of the microaneurysms
PAN
Affects medium and small arteries. Multiple microaneurysms 2-3 cm in size, which when thrombosed produce moth-eaten nephrogram. Angiography has high sensitivity and specificity but a much higher negative than positive predictive value in diagnosis. Diagnosis is often made with
clinical features and angiography.
A 29-year-old female with new onset hypertension has normal renal tract ultrasound. Magnetic
resonance Angiography (MRA) is performed which demonstrates narrowing at the distal right
main renal artery. Which is the most likely diagnosis? [B3 Q26]
A. Renal artery stenosis
B. Fibromuscular dysplasia
C. Arteriosclerotic RA disease
D. Neurofibromatosis
E. Polyarteritis nodosa
Fibromuscular dysplasia
FMD accounts for 35% of RAS. It is more common in children and young adults, affecting females > males. It is associated with hypertension and progressive renal insufficiency. FMD occurs bilaterally in 2 ⁄ 3 of cases and R > L 4:1. It usually affects the mid distal renal artery, and there can be a beaded appearance of artery.
A 55-year-old, hepatitis B-positive male under investigation for painless haematuria is admitted as an emergency with unilateral loin pain and hypotension. A renal arteriogram shows multiple, bilateral, small, renal artery branch aneurysms. Which of the following antibody titres is most likely to be positive? [B4 Q18]
a. anti-double-stranded DNA
b. anti-basement membrane
c. anti-Ro
d. anti-immunoglobulin G
e. perinuclear anti-neutrophil cytoplasmic
Perinuclear anti-neutrophil cytoplasmic - pANCA
While several forms of arteritis can cause multiple small renal aneurysms, it is polyarteritis nodosa that does so most commonly, affecting men more than women with a mean age of 55 years, the range being 18–81 years. It is associated with HIV and hepatitis B infection, and pANCA is usually positive.
Systemic lupus erythematosus: anti-double-stranded DNA antibodies
Goodpasture’s disease: anti-basement membrane antibodies
Sjogren’s syndrome: anti-Ro and anti-La antibodies
rheumatoid arthritis: anti-immunoglobulin G (anti-IgG), also known as rheumatoid factor
A 50-year-old male presents with history of weight loss, hypertension, and headaches. Bloods
show leucocytosis, eosinophilia and raised ESR. A selective renal angiogram shows bilateral,
multiple small vessel aneurysms. The renal arteries are normal. What is the most likely
diagnosis? [B5 Q17]
(a) Rheumatoid disease
(b) Polyarteritis nodosa
(c) Systemic lupus erythematosus
(d) Intravenous drug abuse
(e) Atrial myxoma
Polyarteritis nodosa
Appearances are virtually diagnostic of polyarteritis nodosa. The condition is characterised by
focal areas of necrotising arteritis with fibrinoid necrosis and small aneurysm formation in
skin, kidneys, cardiovascular system, and central nervous system
Which of the following causes immediate faint persistent nephrogram on Intravenous Urogram
(IVU)? [B3 Q13]
A. Renal vein thrombosis (RVT)
B. Acute obstruction
C. Acute hypotension
D. Acute tubular necrosis
E. Chronic obstruction
Acute glomerulonephritis, RVT and chronic severe ischaemia are all causes of immediate faint
persistent nephrogram.
A 54-year-old woman with no history of major illness is incidentally discovered to have a small,
solid enhancing lesion on CT at the lower pole of the right kidney. The CT has been performed
pre and post intravenous contrast. The lesion measures 9 mm in size. What is the most
appropriate management for this lesion? [B1 Q54]
A. Nephron sparing surgery.
B. Percutaneous biopsy.
C. Repeat CT in 3–6 months.
D. Right nephrectomy.
E. Lesion ablation.
Repeat CT in 3–6 months.
Solid masses smaller than 1 cm are challenging. Firstly, there is a reasonable chance that a
very small solid mass is benign. Secondly, it is often difficult to characterize a mass smaller
than 1 cm as solid and enhancing, despite a meticulous technique using state-of-the-art CT
and MR imaging. Thirdly, these masses are often too small to biopsy, therefore when
encountering a mass that is believed to be solid and is less than 1 cm in size, it is reasonable
to observe them with an initial examination with CT or MR at 3–6 months followed by yearly
examinations. A full work-up could ensue when the mass reaches 1 cm in size.
A 28-year-old male with a history of von Hippel Lindau disease and a 3-cm renal cell
carcinoma undergoes cryo-ablation. Which of the following is suggestive of incomplete
treatment/recurrence? [B1 Q62]
A. Hypodense ablation zone larger than the original tumour.
B. Lack of enhancement in the ablation zone.
C. Ablation zone unchanged in size over time.
D. Peripheral ring enhancement.
E. Perinephric fat-stranding post procedure.
Ablation zone unchanged in size over time.
Following ablation, the treatment zone is larger than the original lesion, as a margin of normal
tissue is intentionally ablated to prevent recurrence. This should reduce in size/involute over
time. If the ablation zone remains the same or increases in size, recurrence should be
suspected.
Lack of enhancement is a reliable indicator of successful treatment. It is not uncommon to
find peripheral enhancement in the immediate post-treatment period due to reactive
hyperaemia. Any nodular or central enhancement indicates incomplete treatment or
recurrence.
A 55-year-old man begins to feel unwell after RFA to his right kidney. Considering post-RFA
syndrome, which is the single best answer? [B3 Q1]
A. Flu-like symptoms and myalgia 10 days post procedure
B. Haemorrhage is the most common major complication
C. Urinomas from urine leaks are common
D. Cell death occurs at temperatures higher than 40’C with complete tumour necrosis at 50’ -
60’C
E. Involves conversion of high-pressure argon gas to cold low-pressure liquid by using the
Joule-Thomson effect
Haemorrhage is the most common major complication
Post-RFA syndrome (Flu-like symptoms) occurs 24-48 hours post-ablation. It is a likely inflammatory response to tumour necrosis or cytokine production. Persistence of fever beyond day 10 should be evaluated for infection. Haemorrhage is most seen in central tumours. Ureteral strictures and urinomas are rare.
Which of the following indicates T2 disease in renal cell carcinoma? [B3 Q28]
A. Perinephric fat involvement
B. Tumour size > 2.5cm
C. Tumour involvement of renal vein
D. Tumour involvement of adrenal gland
E. IVC involvement
Tumour size > 2.5 cm
Stage T2 disease is indicated when the tumour size is greater than 2.5cm.
Which of the following most favours RCC rather than TCC? [B3 Q31]
A. A central hypoechoic lesion on US
B. Intraluminal soft tissue mass in the calyx
C. Renal vein invasion
D. Infiltration of renal sinus
E. Contrast outlining tumour in the pelvis
Renal Vein Invasion
In TCC inferior vena cava and renal vein invasion are uncommon
A portal venous-phase CT of the abdomen and pelvis is performed in a 60-year-old man to
investigate upper abdominal and back pain, which is attributed to features of pancreatitis on
the scan. An incidental finding is of a rounded, renal lesion of diameter 3 cm, with average
attenuation value of 80 HU and containing no significant component with a negative
attenuation value on pixel densitometry. There are no previous images for comparison. What
is the most likely diagnosis of the renal lesion? [B4 Q2]
a. angiomyolipoma
b. renal cell carcinoma
c. simple cyst
d. high-density cyst
e. infected cyst
Renal Cell Carcinoma
A single portal venous phase CT is not the optimum image set to characterize renal
parenchymal lesions. However, renal cell carcinoma is more commonly encountered than
high-density cysts. Furthermore, carcinoma is most frequently found in men (2:1) aged over
50 years. Kidney neoplasms tend to have densities above 30 HU on an unenhanced CT and
rise by more than 10–20 HU post-contrast, usually being above 70 HU in the portal phase
CT scan of the chest, abdomen and pelvis is performed to stage a renal cell carcinoma. The
tumour arises in, and is confined to, the upper pole of the left kidney with a maximum
dimension of 5 cm. There is tumour thrombus in the left renal vein, inferior vena cava and right
atrium. There are no enlarged lymph nodes and no metastases seen. According to the TNM
classification what is the stage of the tumour? [B4 Q9]
a. T4 N0 M0
b. T2 N0 M0
c. T3a N0 M0
d. T3c N0 Mx
e. T3c N0 M0
T3c N0 M0
T1 <7 cm - Limited to kidney
T2 >7cm - Limited to kidney
T3 tumour extends beyond the kidney, into either the adrenal gland or
perinephric tissues (T3a), the renal vein or vena cava below the diaphragm (T3b) or the vena
cava above the diaphragm, or it invades the wall of the vena cava (T3c).
T4 tumour invades beyond Gerota’s fascia.
N1 or N2 nodal disease refers to involvement of a single regional node, or more than one regional node, respectively. Overall, T3c N0 M0 disease represents stage III disease
An 80-year-old male with a history of nephrectomy for renal cell carcinoma is found at follow-
up to have a heterogeneously enhancing 25 mm lesion confined to his remaining kidney. No
enlarged nodes or metastases are present. The lesion is biopsied and found to be an
adenocarcinoma. The patient decides upon radiofrequency ablation as treatment. A CT scan 1
month after the ablation quantifies the average post-contrast enhancement of the tumour as 8
HU. Which of the following best represents the degree of success of the radiofrequency
ablation? [B4 Q27]
a. failed
b. residual enhancing tumour requiring repeat ablation
c. residual enhancing tumour but no value in repeat ablation
d. successful
e. indeterminate
Successful
The practice of radiofrequency ablation of renal tumours is emerging. Currently, CT 1 month
after the procedure is used to assess treatment success. If enhancing prior to ablation, the
tumour is regarded as ablated if there is <10 HU rise in attenuation following contrast
administration. Bulky persistent irregular peripheral enhancement is the commonest
appearance of an incompletely treated lesion
A 35-year-old male with autosomal dominant polycystic kidney disease has been shown on CT
to have, among the innumerable renal cysts, several high-density cysts. Which of the following
MRI sequences would be most useful in detecting a renal cell carcinoma among haemorrhagic
or proteinaceous cysts? [B4 Q34]
a. T1W
b. T2W
c. T1W post-gadolinium
d. T1W fat-suppressed post-gadolinium
e. T1W post-gadolinium with pre-contrast T1W signal subtracted
T1W post-gadolinium with pre-contrast T1W signal subtracted
The cornerstone of diagnosis here is the post-contrast enhancement of renal cell carcinoma.
To identify this among the high T1 signal of haemorrhage or protein within cysts, it is ideal to subtract the precontrast T1 signal. Fat suppression will not remove the distracting high signal from mildly complicated cysts. Risk of renal cell carcinoma is increased in adult polycystic renal disease when in renal failure. Hence, caution may be required since at certain levels of renal impairment the use of MRI contrast is not advised.
A 60-year-old man has a 4 cm rounded mass arising within the right kidney. It has
heterogeneous, strong post-contrast enhancement. Calcification is also evident within the
tumour. Which of the following features of this renal mass would favour the diagnosis of renal
cell carcinoma over angiomyolipoma? [B4 Q84]
a. marked vascularity
b. calcification
c. fat within the tumour
d. round morphology
e. hyperechogenic on ultrasound scan
Calcification
No calcification in AML whereas it is seen in 10% of renal cell carcinomas. Both these tumours can be hyper vascular. The cornerstone of diagnosis of an angiomyolipoma is identifying fat on CT or MRI; however, fat has been reported in renal cell carcinoma, and peripheral or renal sinus fat can become trapped in any large renal tumour
An adult male is initially investigated for abnormal liver function tests. Eventually, the
diagnosis of Stauffer’s syndrome is pronounced. What are the likely CT findings? [B4 Q96]
a. liver mass in keeping with hepatocellular carcinoma with renal metastases
b. renal mass in keeping with renal cell carcinoma with liver metastases
c. renal mass in keeping with renal cell carcinoma and hepatosplenomegaly without focal
hepatic or splenic lesions
d. hepatosplenomegaly and bilateral renal enlargement without focal lesions in any of these
organs
e. renal mass in keeping with renal cell carcinoma with a pancreatic head metastasis
Renal mass in keeping with renal cell carcinoma and hepatosplenomegaly without focal
hepatic or splenic lesions.
Stauffer described a syndrome of nephrogenic hepatopathy in which a renal cancer without
liver metastases causes hepatosplenomegaly and abnormal liver function. Renal cell
carcinoma paraneoplastic phenomena include erythrocytosis and hypercalcaemia
A 67-year-old male patient presents with an 8-week history of left loin pain. A renal CT is
obtained, and this shows a 6-cm enhancing left renal lesion that has a fibrotic central scar. What
is the most likely diagnosis? [B1 Q14]
A. Renal leiomyoma.
B. Renal oncocytoma.
C. Renal metanephic adenoma.
D. Renal haemangioma (giant).
E. Renal juxta-glomerular cell neoplasm
Renal oncocytoma.
This is a benign renal cell neoplasm responsible for about 5% of all adult primary renal
epithelial neoplasms. It typically occurs in elderly men. They usually appear as solitary, well-
demarcated, unencapsulated, fairly homogeneous renal cortical tumours with central stellate scar.
Bilateral, multicentric oncocytomas are seen in hereditary syndromes of renal oncocytosis and Birt–Hogg–Dubé syndrome. A central stellate scar is seen in approximately one-third. However, distinguishing them from RCC on imaging is not reliable.
Leiomyoma of the kidney is a benign smooth muscle neoplasm. It appears as a well-
circumscribed, homogeneous, exophytic solid mass that shows uniform enhancement on
contrast-enhanced CT. It may occasionally be cystic.
Metanephric adenoma is a benign renal neoplasm that is more common in middle-aged to
elderly females. It is associated with polycythaemia in 10%. It typically appears as a well-
defined, unencapsulated, solitary mass that may be hyperattenuating on unenhanced CT.
Calcification can be seen in up to 20%.
Hemangioma of the kidney occurs as an unencapsulated, solitary lesion that frequently arises
from the renal pyramids or the pelvis. Contrast-enhanced CT or MRI may show early intense
enhancement, with persistent enhancement on delayed images.
Juxtaglomerular cell (JGC) neoplasm or reninoma is an extremely rare, benign renal neoplasm
of myoendocrine cell origin, which is associated with a clinical triad of hypertension,
hypokalaemia, and high plasma renin activity. It typically appears as a unilateral, well-
circumscribed, cortical tumour and often measures less than 3 cm, but otherwise is
indistinguishable from other cortical neoplasms.
A 65-year-old male has a renal ultrasound scan for right flank pain which demonstrates a 7 cm
solid mass within the right kidney with a hypoechoic centre. Subsequent CT scan of the chest,
abdomen and pelvis reveals the lesion to have a low-attenuation central scar. There is no renal
vein invasion or evidence of malignancy elsewhere in the body. Which of the following is the
most likely diagnosis? [B2 Q9]
a. Lymphoma of the kidney
b. Transitional cell carcinoma
c. Collecting duct tumour
d. Oncocytoma
e. Nephroblastoma
Oncocytoma
Benign. Oncocytoma is a tubular adenoma that is very rarely malignant. They are often asymptomatic even when large. The central scar is typical and is due to haemorrhage and infarction of the tumour having outgrown its vascular supply.
Radiological differentiation from renal cell carcinoma can be very difficult and percutaneous needle biopsy is unreliable. Nephrectomy is therefore often indicated
Oncocytosis is considered in a 50-year-old man with bilateral renal masses. Which is the single
best answer regarding oncocytosis? [B3 Q3]
A. Account for 2% of all renal cortical tumours
B. Multifocality bilateralism and metachronous tumours occur together in 4-6%
C. In multifocal cases co-existent RCC is present in 50% of cases
D. Often have preserved renal function
E. The final diagnosis can be made on MR above
Multifocality bilateralism and metachronous tumours occur together in 4-6%
Co-existent RCC in 10% of cases. Due to diffuse bilateral renal involvement patients with
oncocytosis often present with abnormal renal function. Final diagnosis is by biopsy
A 12-month-old infant with a history of aniridia and nephroblastomatosis undergoes a follow-
up CT of abdomen that demonstrates bilateral enlarged kidneys with a thick rind of
homogenous, non-enhancing, hypodense tissue bilaterally. A focal heterogenous enhancing
mass with cystic change is noted on one side. What is the diagnosis? [B1 Q57]
A. Neuroblastoma.
B. Wilms tumour.
C. Lymphoma.
D. Renal cell carcinoma.
E. Cystic nephroma.
Wilms tumour.
Sporadic aniridia is associated with nephron-blastomatosis (multiple nephrogenic rests) and
an increased risk of Wilms tumour. At CT, the nephrogenic rests appear as homogenous,
hypodense nodules/peripheral rind, with little or no enhancement compared to the
compressed normal cortical tissue.
Any new, enlarging, or heterogenous mass in the setting of nephron-blastomatosis indicates
the development of a Wilms tumour.
A 4-year-old child was referred for a palpable abdominal mass and abdominal pain. Ultrasound
shows a large heterogenous mass in the abdomen. Contrast enhanced CT demonstrates a large
heterogenous and necrotic mass arising from the right kidney, extending across the midline,
and displacing the aorta and inferior vena cava. There are calcifications within the lesion. What
is the most likely diagnosis? [B5 Q31]
(a) Neuroblastoma
(b) Nephroblastoma
(c) Renal cell carcinoma
(d) Oncocytoma
(e) Hepatoblastoma
Nephroblastoma
Also called Wilms’ tumour, this lesion typically presents as a large mass, crossing the midline
and commonly displacing the large vessels (in contrast to neuroblastoma, where the mass
encases the vessels). This is the most common neoplasm in children between 1 and 8 years
of age.
Considering Squamous Cell Carcinoma (SCC) of the kidney: [B3 Q32]
A. Is the second most common tumour subtype affecting the kidney
B. Usually carries a better prognosis than RCC
C. Is usually indolent
D. Acute infection is involved in the aetiology
E. Renal calculi are present in most patients
Renal calculi are present in most patients
SCC of the kidney is a relatively rare condition. It carries a poor prognosis due to its aggressive
nature. Both renal calculi and chronic infection have been implicated in its aetiology. Cross
sectional imaging appearances are identical to those of TCC
A 3-month-old baby presents with an abdominal lump. Ultrasound shows a large solid mass
arising from the right kidney with focal hypoechoic areas. Contrast enhanced CT shows a solid
right renal mass, involving the renal sinus and multiple small areas of necrosis. There is no
invasion of the renal vein or the collecting system. No metastatic deposits are seen. What is the
most likely diagnosis? [B5 Q44]
(a) Wilms’ tumour
(b) Mesoblastic nephroma
(c) Nephro-blastomatosis
(d) Renal metastases
(e) Lymphoma of kidney
Mesoblastic nephroma
This is a hamartoma and is the most common solid neoplasm in neonates. It typically involves
the renal sinus and there is no invasion of the veins (differentiating it from Wilms’ tumour) or
the collecting system. small areas of necrosis
A 46-year-old woman has an incidentally discovered large mixed echogenicity mass in the left
flank on an ultrasound examination. A follow-up CT examination is performed, and this shows
a predominantly fatty lesion exophytic to the left kidney, measuring approximately 12 cm in
maximum diameter. Which of the following findings would make the diagnosis of large renal
angiomyolipoma more likely than a perirenal well-differentiated retroperitoneal liposarcoma?
[B1 Q10]
A. The presence of mass effect with displacement of the left kidney.
B. The presence of aneurysmal blood vessels within the lesion.
C. The presence of soft-tissue density areas within the lesion.
D. The presence of ill-defined margins.
E. The presence of fluid density components
The presence of aneurysmal blood vessels within the lesion.
Both well-differentiated retroperitoneal liposarcomas and exophytic renal angiomyolipomas
can be very large in size and thus size is not a discriminating factor. Both contain large
amounts of mature lipid, thus significant portions of the lesion will have negative Hounsfield
attenuation values on CT imaging.
Aneurysmal blood vessels are commonly seen in large angiomyolipomas, whereas well
differentiated liposarcomas are generally rather hypo-vascular lesions. Both
angiomyolipomas and retroperitoneal liposarcomas may contain areas of soft tissue density.
Liposarcoma is probably more likely to have an irregular margin and may contain areas of
fluid density
A 23-year-old female has a renal ultrasound scan for recurrent urinary tract infections. The
only abnormality detected is a 3cm hyperechoic mass in the upper pole of the left kidney. She
subsequently undergoes CT which shows the lesion to have an average HU of–10. Which of
the following is the most likely diagnosis? [B2 Q7]
a. Renal cell carcinoma
b. Transitional cell carcinoma
c. Renal lymphoma
d. Angiomyolipoma
e. Renal abscess
Angiomyolipoma
The finding of fat attenuation values within a renal lesion on CT is diagnostic of
angiomyolipoma. This is a benign tumour that is typically hyperechoic on ultrasound and of
high signal on T1-weighted MR due to fat. It does not enhance post-gadolinium, in contrast
to renal cell carcinoma, which usually does enhance
In a 40-year-old woman with seizures and bilateral renal masses, with the appearance of
multiple angiomyolipomas, which is the single best answer? [B3 Q9]
A. Sporadic solitary Angiomyolipoma (AML) have a female preponderance
B. Account for 50% of all renal AMLs
C. Are associated with tuberous sclerosis
D. Warrant treatment due to risk of bleeding when > 2cm
E. Are typically hypoechoic on US
Are associated with tuberous sclerosis
Those AML associated with tuberous sclerosis are multifocal, bilateral, larger and present in
a younger age group. AML appear echogenic on US.
During MR of the spine a 2 cm renal lesion is identified at the upper pole cortex of the RK.
The lesion is well-defined and is of high SI on T1 and T2 images. Ultrasound shows normal
Doppler flow in the renal vein which is separate from the lesion, which is echogenic on US.
The findings are most likely to represent which of the following? [B3 Q12]
A. AML
B. Atypical cyst
C. Abscess
D. RCC
E. Lymphoma
AML
AML appears increased on S1 on T1+T2 and is echogenic on US.
In a patient who had a right nephrectomy ten years ago for RCC, a 3cm lesion in the cortex of
the lower pole of the left kidney is evaluated with MRI. This appears isointense on the in-phase
sequence and low SI on the opposed phase sequence. No other renal lesions are demonstrated.
The renal veins appear normal. What is the most likely diagnosis? [B3 Q21]
A. AML
B. Simple cyst
C. Oncocytoma
D. RCC
E. Metastatic deposit
AML
Demonstration of fat within a renal mass on CT or MRI is diagnostic of AML
A 60-year-old female who has declined intervention for a renal angiomyolipoma of diameter
6 cm presents with flank pain, hypotension and tachycardia. In this scenario, which of the
following is most likely to account for the presentation? [B4 Q71]
a. torsion of the angiomyolipoma
b. haemorrhage from the angiomyolipoma
c. rupture of the angiomyolipoma
d. leak from the non-aneurysmal abdominal aorta
e. nephroptosis
haemorrhage from the angiomyolipoma
Angiomyolipomas are benign hamartomatous tumours that can occur in the kidneys. They
contain fat, smooth muscle and abnormal blood vessels. Eighty per cent are sporadic and
occur most often in females aged 50–80 years. Twenty per cent of patients with
angiomyolipomas have tuberous sclerosis. Retroperitoneal bleed is the most significant
complication and can be catastrophic. The risk increases with size of the lesion due to
increased abnormal vasculature. Haemorrhage occurs because of large tortuous vessels and
aneurysms. Embolization is performed for symptomatic (flank pain) angiomyolipomas, those
that have bled at any size, and prophylactically when over 4cm.
A 42-year-old man with a history of fits presents with recurrent abdominal pain. Ultrasound
shows a 4 cm heterogenous lesion in the upper pole of the right kidney, with moderate
vascularity. Contrast-enhanced CT shows that the lesion predominantly contains tissue with
Hounsfield units of -65 to -80. Other smaller such lesions were also seen in the left kidney.
What is the most likely diagnosis? [B5 Q25]
(a) Multifocal renal cell carcinoma
(b) Angiomyolipomas
(c) Lymphoma
(d) Metastases
(e) Multiple lipomas
Angiomyolipomas
The lesions contain fat (negative Hounsfield units) and show vascularity within. With the
history of fits, tuberous sclerosis should be considered as a diagnosis.
A 65-year-old male undergoes renal CT following the finding of multiple hypoechoic masses
in both kidneys on ultrasound. Multiple poorly defined masses of decreased attenuation are
demonstrated, which encase the renal vessels. The vessels remain patent, however, and the
renal contour is preserved. Which of the following is most likely to represent the underlying
diagnosis? [B2 Q45]
a. Renal cell carcinoma
b. Transitional cell carcinoma
c. Multiple myeloma
d. Non-Hodgkin’s lymphoma
e. Reninoma
Non-Hodgkin’s lymphoma
The most likely diagnosis is non-Hodgkin’s lymphoma. Primary renal involvement is rare but
is often involved either by haematogenous spread or direct invasion. The kidneys represent
one of the most common extra-nodal sites of disease in non-Hodgkin’s lymphoma but are
rarely involved in Hodgkin’s disease. Involvement is usually bilateral, with masses of
decreased attenuation and mild homogenous enhancement with intravenous contrast on CT.
Patency of the renal vessels despite encasement is highly suggestive, as is preservation of the
normal renal contour.
Regarding lymphoma of the kidneys: [B3 Q29]
A. Multiple focal nodules appear hyperdense on CT
B. Involved kidneys are usually atrophic
C. Focal masses appear high signal on T1
D. Focal masses appear hyperintense on T2
E. CT may demonstrate sheet like diffuse infiltration of perirenal tissues
CT may demonstrate sheet like diffuse infiltration of perirenal tissues
Diffuse infiltration leads to renal enlargement. Focal lesions have a characteristic usually low
attenuation post-contrast on CT, low SI on T1 and hypo-iso-intense on T2
Regarding metastatic sites of disease to the kidney: [B3 Q30]
A. Are frequently symptomatic
B. Usually occurs from direct invasion
C. Haematogenous metastasis are usually > 3 cm
D. Are usually hypo-vascular on CT
E. Commonly calcifies
Are usually hypo-vascular on CT
Metastases are usually small (< 3cm), multiple and confined to cortex. The most common
mode of spread is haematogenous. Metastases tend not to invade the renal vein or calcify;
they are more infiltrative, less exophytic compared with renal cell carcinoma
A 40-year-old man has an ultrasound examination of the abdomen for epigastric pain. The
examination is normal apart for an isoechoic ‘mass’ at the mid-pole of the left kidney. You
suspect this may be a normal variant, such as a prominent column of Bertin. You recommend
a CT scan of kidneys to confirm this. Which phase of a CT renal tract examination would best
show this variant? [B1 Q33]
A. Unenhanced scan.
B. Cortico-medullary phase.
C. Nephrographic phase.
D. Early excretory (3-minute) phase.
E. Late excretory (10-minute) phase
Cortico-medullary phase.
Imaging in the cortico-medullary phase (25-40 sec) is helpful for showing the normal cortico-medullary
pattern in pseudotumours such as prominent columns of Bertin or focal renal hypertrophy. It is also useful
for suspected abnormalities such as vascular malformations and pseudoaneurysms of the kidney.
The nephrographic phase (70-180 sec) is best to characterize renal masses. Small parenchymal renal lesions may be hidden in the renal medulla on the cortico-medullary phase and excretory phases.
Excretory phases(>180 sec) are best to assess for collecting system lesions and the unenhanced scan is
best for detection of renal calculi and for using as a baseline in assessing the enhancement
characteristics of parenchymal renal lesions
A 43-year-old female has a renal ultrasound which shows a left-sided renal ‘mass’. The ‘mass’
is continuous with the renal cortex and has the same echogenicity as the cortex. It is situated at
the border of the upper and mid poles of the left kidney and is seen to extend between the renal
pyramids. Which one of the following are these features most likely to represent? [B2 Q55]
a. Renal scarring
b. Hypertrophied column of Bertin
c. Dromedary hump
d. Persistent fatal lobulation
e. Duplex kidney
Hypertrophied column of Bertin
Many lesions may be mistaken for a renal cell carcinoma on imaging, and it is important to be able to differentiate such ‘pseudotumours’ from genuine carcinomas. The features described in the question are consistent with a prominent column of Bertin. This is normal renal tissue located between the pyramids and extending into the renal sinus. The key features include continuity with the cortex, identical echogenicity to normal cortex and the lack of mass effect or renal outline deformity.
- A dromedary hump is a focal bulge on the lateral border of the left kidney caused by
its relationship with the adjacent spleen. - Persistent fetal lobulation can be identified by indentations of the renal surface that
overlie the space between the pyramids - Renal scarring lies directly over the medullary pyramids
A 35-year-old man with a facial ‘port-wine stain’ and history of epilepsy presents with
haematuria. Contrast-enhanced CT abdomen shows vascular malformations in the kidney and
spleen. What is the most likely diagnosis? [B5 Q47]
(a) von Hippel–Lindau disease
(b) Sturge–Weber–Dimitri syndrome
(c) Neurofibromatosis type 1
(d) Neurofibromatosis type 2
(e) Tuberous sclerosis
Sturge–Weber–Dimitri syndrome
This is characterised by multiple vascular malformations in the face (‘port-wine stain’) and
central nervous system (leptomeningeal venous angiomas), and orbital and visceral
angiomatosis (intestine, kidneys, spleen, thyroid, pancreas, and lungs).
Syndromes with renal mass
- Von-Hippel Lindau
- Tuberous Sclerosis
- Birt Hogg Dube
- Sturge-Weber-Dimitri
A 60-year-old man has an unenhanced CT scan of renal tracts for suspected right renal colic.
The examination is normal apart from an exophytic rounded lesion at the mid-pole of the left
kidney, which is denser than adjacent renal parenchyma. You elect to perform an intravenous
contrast enhanced examination in the nephrographic phase to further evaluate this lesion.
Which of the following Hounsfield attenuation values would be most appropriate if this lesion
is benign? [B1 Q49]
A. 20 pre-contrast attenuation, 30 post-contrast attenuation.
B. 30 pre-contrast attenuation, 60 post-contrast attenuation.
C. 40 pre-contrast attenuation, 50 post-contrast attenuation.
D. 50 pre-contrast attenuation, 80 post-contrast attenuation.
E. 60 pre-contrast attenuation, 70 post-contrast attenuation.
F. 70 pre-contrast attenuation, 100 post-contrast attenuation
60 pre-contrast attenuation, 70 post-contrast attenuation.
The attenuation of the normal renal parenchyma typically ranges from 30 to 40 HU. That of
hyperattenuating renal masses usually is at least 40 HU but no higher than 90 HU on CT
without intravenous contrast. Benign cysts are overwhelmingly the most common type of
hyperattenuating renal mass and are also known as hyperdense renal cysts. They are usually
cysts containing haemorrhage or proteinaceous material. Hyperattenuating cysts should not
enhance and therefore cannot be diagnosed with confidence by using unenhanced CT alone.
A proper CT examination includes scanning both before and after the administration of
intravenous contrast material. Masses that increase in attenuation by 10 HU or less are
considered non-enhancing. Masses that increase in attenuation by more than 10 HU are
considered enhancing. However, because the standard deviation of attenuation
measurements may be more than 10 HU, an attenuation difference of 20 HU or more is a
more specific criterion of enhancement
A 45-year-old man has a complex cyst identified in the right kidney on an ultrasound scan
performed to assess non-specific epigastric pain. He subsequently has a CT scan of kidneys
carried out pre and post administration of intravenous contrast. You classify the complex cyst
as IIF (II requiring follow-up) according to the Bosniak classification. Which of the following
features is most likely seen at CT imaging? [B1 Q59]
A. Presence of calcification.
B. Thickened smooth wall with enhancement.
C. Multiple thin non-enhancing septa.
D. Hyperattenuating cyst <3 cm in size.
E. Thickened irregular wall.
Multiple thin non-enhancing septa.
The criteria for a Bosniak IIF cyst are multiple hairline-thin septa with or without perceived (not measurable) enhancement, minimal smooth thickening of wall or septa that may show perceived (not measurable) enhancement, calcification may be thick and nodular but no measurable enhancement present, no enhancing soft-tissue components, and intrarenal non-enhancing high attenuation renal mass (> 3cm). The follow-up is CT or MRI at 6 months, 1 year, and then yearly up to 5 years.
The criteria for a Bosniak II cyst that does not require follow-up include few hairline-thin septa
with or without perceived (not measurable) enhancement, fine calcification or a short
segment of slightly thickened calcification in the wall or septa, homogeneously high-
attenuating masses (<3 cm) that are sharply marginated and do not enhance.
Thickened irregular or smooth walls or septa, with measurable enhancement, are features of
a Bosniak III cyst and these are surgical lesions unless there are co-morbidities or limited life
expectancy, when they may be observed
A 71-year-old male undergoes renal CT for characterisation of a cystic renal mass. Which one
of the following five features would classify the lesion as a Bosniak III lesion? [B2 Q21]
a. Lack of enhancement
b. Septation
c. Minimally irregular wall
d. Curvilinear calcification
e. Uniform wall thickening
Uniform wall thickening
The Bosniak classification groups cystic renal lesions into one of four categories based on
CT/MR appearances. The differentiation between groups II and III is important as group II are
typically ‘follow-up lesions and group III are ‘surgical lesions. Features of a Bosniak III lesion
include irregular thickened septa, measurable enhancement, coarse irregular calcification,
multi-loculation, nodularity, uniform wall thickening and margin irregularity
A 3 cm cystic lesion is seen on CT. Thickened septae are noted, with nodular areas of
calcification, with solid non-enhancing areas. Which of the following Bosniak classification
best describes the lesion? [B3 Q27]
A. I
B. II
C. IIF
D. III
E. IV
III
Class II have at least one thin septa traversing them (< 1mm) and they have an appearance of
thin areas of mural calcification or fluid content with greater attenuation. These lesions are
benign however IIF with numerous class II features should be followed up. Class III features
as above are indicative of malignancy and biopsy, or surgical exploration is necessary. Type IV
cystic lesions are clearly malignant.
A 55-year-old male has an ultrasound scan of the renal tract prompted by a single urinary tract
infection. A kidney cyst of diameter 2 cm with a thin septum is seen. The septum has
perceptible enhancement on CT. What is the most appropriate management from the choices
below? [B4 Q4]
a. discharge with no follow-up
b. imaging follow-up
c. partial nephrectomy
d. nephrectomy
e. nephroureterectomy
Imaging follow-up
An incidental, mildly complicated renal cyst has been uncovered. The Bosniak classification is
a useful tool for evaluating cystic renal lesions, and guiding management. Simple cysts
(Bosniak grade I) are thin walled, are of water density and have no enhancement. Minimally
complicated cysts (grade II) may be clustered or septated, and have small curvilinear
calcifications, a minimally irregular wall or high-density contents. Follow-up lesions (grade IIF)
have perceptible enhancement of otherwise thin septations or are above 3cm in diameter
with high-density contents. Surgical lesions (grade III) have thicker septa or walls, measurable
enhancement, coarse irregular calcification and irregular margin, are multiloculated or can be
a non-enhancing nodular mass. Clearly malignant lesions (grade IV) can have necrotic
components, irregular wall thickening and enhancing solid elements
A 50-year-old man is discovered to have a cystic abnormality at the lower pole of the left
kidney during an ultrasound scan performed for right upper quadrant pain. You think this might
be a complex cystic lesion and therefore recommend a CT scan of renal tracts. This shows a
conglomeration of variable sized cysts at the lower pole of the left kidney, but no capsule or
mural irregularities of the cysts. What is the most likely diagnosis? [B1 Q72]
A. Localized cystic renal disease.
B. Multilocular cystic nephroma.
C. Renal lymphangiomatosis.
D. Cystic clear cell carcinoma.
E. Multicystic dysplastic kidney
Localized cystic renal disease.
This is an uncommon, non-familial, and non-progressive disorder of the kidney characterized
by the replacement of all or localized areas of a kidney by multiple variably sized cysts. These
cysts form clusters that are separated by thin areas of normal renal parenchyma. The
aggregated cysts in localized cystic disease can frequently appear like a multi-septate mass,
but they do not form a distinct encapsulated mass and do not show mural irregularities, which
are characteristics of cystic neoplasms.
Multilocular cystic nephroma in adults is much more common in females (female:male 9:1)
and manifests as a multi-loculated cystic lesion with hair-like septa and minimal mural
enhancement. It is distinguished from localized cystic disease by the presence of a capsule.
Typically, extension into the central renal sinus is found and multilocular cystic nephroma is
often classified on imaging as Bosniak III lesions.
Lymphangioma of the kidney is a rare benign cystic tumour that most often arises from the
peri-pelvic region or renal sinus. It may more rarely arise from the lymphatics of the capsule
or cortex. In the diffuse form of lymphangiomatosis, the cystic changes occur diffusely in the
renal sinus or perinephric region, with a relatively normal appearing renal parenchyma.
Clear cell RCC presents as a solid or a cystic lesion, the cystic variant accounting for 4–15% of
all RCCs. These lesions typically have nodular or septal enhancement, distinguishing them
from benign cystic renal lesions.
Multi-cystic dysplastic kidney is a congenital maldevelopment in which the kidney is
completely replaced by cysts with no normal renal parenchyma remaining.
A 50-year-old female undergoes CT for an echogenic renal lesion on ultrasound. Pre-contrast
CT shows a lesion, which is well-defined and has increased attenuation (60 HU). Postcontrast
the lesion appears low in attenuation related to the surrounding parenchyma (61 HU). The
diagnosis is: [B3 Q47]
A. Haemorrhagic renal cell carcinoma
B. Angiomyolipoma (AML) that has bled
C. Lymphoma
D. Haemorrhagic renal cyst
E. AML
Haemorrhagic renal cyst
A less than 10 HU increase post-contrast indicates benign hyperdense cyst. Other benign
features include being sharply marginated and homogenous
A 36-year-old labourer working on a building site falls 15 feet from scaffolding on his back
onto a wheelbarrow. He is catheterized in the resuscitation room and is noted to have gross
haematuria. Which of the following CT findings are consistent with a grade 4 renal injury? [B1
Q53]
A. Renal artery avulsion.
B. Shattered kidney.
C. Deep laceration to the collecting system.
D. Subcapsular haematoma.
E. Parenchymal contusion
Deep laceration to the collecting system.
Renal injuries are classified into five grades of severity by the
American Association for the Surgery of Trauma (AAST), with
approximately 80% classified as grade 1. Most significant
injuries manifest as haematuria and no significant urinary tract
injury occurs in the absence of gross haematuria and shock. In
addition, most significant renal trauma is associated with
additional visceral injury.
A 22-year-old male front seat passenger is admitted following a RTA. On examination in A&E,
blood is noted at the external urethral meatus and there is swelling of the penis. An urethrogram
is performed which demonstrates contrast extravasation below the urogenital diaphragm only.
What type of urethral injury does this represent? [B1 Q63]
A. Anterior urethral injury.
B. Disruption of the membranous urethra.
C. Bladder neck injury extending into the proximal urethra.
D. Bladder base injury.
E. Penile fracture.
Anterior urethral injury.
Urethral injuries are rarely life-threatening but have significant long-term morbidity.
Complications include stricture, incontinence, and impotence. The male urethra extends from
the bladder base to the external meatus and is divided into the posterior (prostatic and
membranous) and anterior (bulbous and penile) urethra. The anterior and posterior urethra
are separated by the urogenital diaphragm. The Goldman classification of urethral injury
emphasizes anatomic location.
