GENITOURINARY IMAGING 1 Flashcards
Are cystine stones a/w increased urine pH?
? % of stones composed of cystine?
Between 1% and 2% of calculi are composed of cystine and are caused by genetic defects in renal amino acid resorption.
7 Primary Bladder neoplasms
Bladder Neoplasms
-
Primary
- TCC
- SCC
- Adenocarcinoma
- Pheochromocytoma from bladder wall paraganglia (10% are malignant)
- Rare tumors
- rhabdomyosarcoma
- leiomyosarcoma
- primary lymphoma
What is the cut off for Thickened Endometrial Stripe thickness?
Thick Hyperechoic Ems ( Fig. 4.64 )
Criteria:
- greater than 5 mm in postmenopausal patients with bleeding
- greater than 14 mm in premenopausal patients (varies with stage in cycle)
7 DDx of Renal Sinus Mass
2 categories
- Renal Sinus Mass
- Tumors
- TCC
- RCC
- Lymphoma
- Bellini duct carcinoma
- Other
- Renal artery aneurysm
- Renal sinus hemorrhage
- Complicated parapelvic cyst
- Tumors
5 Ddx of Tubal Irregularity
Tubal Irregularity
- SIN (Salpingitis isthmica nodosa)
- Tubal diverticula
- Endometriosis
- Postoperative changes
- TB
Salpingitis isthmica nodosa (SIN) occasionally referred to as diverticulosis of the fallopian tube is a common finding in patients investigated for ectopic pregnancies or infertility. Its etiology is still debated, however, it is likely the result of an acquired process. The management of SIN is aimed at restoring and maintaining fertility.
10 ddx of Delayed (Persistent) Nephrogram
ie 10 DDx of Renal Failure
3 categories
10 pathologies
18 eitiologies
Delayed (Persistent) Nephrogram (Same DDx as Renal Failure)
-
Prerenal causes (15%)
- Renal artery stenosis
- Hypotension
-
Renal causes (70%)
- Acute glomerulonephritis
- ATN
- radiographic iodinated contrast agents (only in patients with GFR <30)
- antibiotics
- anesthesia
- ischemia
- transplants
- Acute cortical necrosis
- pregnancy related, 70%
- sepsis
- dehydration
- Tubular precipitation
- uric acid
- hemolysis
- myeloma
- Acute interstitial nephritis
- antibiotics
- Papillary necrosis
- analgesic
- sickle cell
- DM
- Renal vein thrombosis
-
Postrenal causes (15%)
- Obstruction
- stone
- stricture
- Obstruction
Rule of thumb
- Symmetrical, bilateral: medical disease
- Asymmetrical, unilateral: surgical disease
Medullary Calcinosis
HHMMRS
- medullary sponge kidney
- hyperparathyroidism
- Renal tubular acidosis
- Hypervitaminosis D
- Milk-alkali
- sarcoid
11 ddx of Cystic ovarian Mass
Ovary
- Normal ovarian cysts (physiologic)
- Follicle (mean diameter <25 mm);
- follicular cyst (mean diameter >25 mm)
- Corpus Luteum Cyst
- Too many follicles:
- polycystic ovary,
- hyperstimulation syndrome
- Theca lutein cyst
- with high levels of β-HCG
- Cystic adnexal masses
- Hemorrhagic cyst
- Endometrioma
- “chocolate cyst”
- Ectopic pregnancy
- Cystadenocarcinoma
- TOA
Child with horse shoe kidney and fat?
A turners
B Prader Willi
C Di George
A - Turners syndrome
Horseshoe kidney
Dr Pir Abdul Ahad Aziz◉ and Assoc Prof Frank Gaillard◉◈ et al.
Horseshoe kidneys are the most common type of renal fusion anomaly. They render the kidneys susceptible to trauma and are an independent risk factor for the development of renal calculi and transitional cell carcinoma of the renal pelvis.
Epidemiology
Horseshoe kidneys are found in approximately 1 in 400-500 adults and are more frequently encountered in males (M:F 2:1) 1-3. The vast majority of cases are sporadic, except for those associated with genetic syndromes (see below) 3.
Clinical presentation
Horseshoe kidneys are, in themselves, asymptomatic and thus they are usually identified incidentally. They are however prone to a number of complications as a result of poor drainage, which may lead to clinical presentation. These complications include:
hydronephrosis, secondary to pelviureteric junction obstruction
renal calculi: up to 60% of patients 11
increased susceptibility to trauma 11
infection and pyeloureteritis cystica
increased incidence of malignancy
Wilms tumor 11,12
transitional cell carcinoma (TCC) of the renal pelvis 12
renal carcinoid 9
renovascular hypertension 7,8,10
Pathology
Embryology
A horseshoe kidney is formed by fusion across the midline of two distinct functioning kidneys, one on each side of the midline. They are connected by an isthmus of either functioning renal parenchyma or fibrous tissue. In the vast majority of cases, the fusion is between the lower poles (90%) 13. In the remainder, the superior, or both the superior and inferior poles are fused. This latter configuration is referred to as a sigmoid kidney 3.
The normal ascent of the kidneys allows the organs to take their place in the abdomen below the adrenal glands. However, with a horseshoe kidney, ascent into the abdomen is restricted by the inferior mesenteric artery (IMA) which hooks over the isthmus. Hence horseshoe kidneys are low lying.
As a result of this fusion the inferior pole of each kidney point medially which is the reverse of the normal renal axis. The ureters leave the kidneys and pass anterior to the isthmus, which is typically located immediately below the inferior mesenteric artery.
Also due to the halted ascent, renal vascular anomalies are common: usually, multiple renal arteries arise from the distal aorta or iliac arteries; this is important when these patients undergo any procedure, particularly a renal angiogram.
Associations
Horseshoe kidneys are frequently associated with both genitourinary and non-genitourinary malformations, and are also seen as part of a number of syndromes 3:
chromosomal/aneuploidic anomalies
Down syndrome
Turner syndrome: up to 7% have a horseshoe kidney
Edwards syndrome (trisomy 18): up to 20% have a horseshoe kidney
Patau syndrome (trisomy 13)
non-aneuploidic anomalies
Ellis-van Creveld syndrome 2
Fanconi anemia 1
Goltz syndrome
Kabuki syndrome
Pallister-Hall syndrome
VACTERL association
Palpable mass in the left middle abdomen. Allergy to iodinated contrast.
Large multilocular cystic mass of the left kidney with fluid-equivalent and atypical cysts, no intracystic enhancement.
Case Discussion
Histopathology report: multiple, partly hyalinised connective tissue septae with round cell infiltration and pigmented foam cell aggregates. Predominantly one-layered, eosinophilic epithelial cystic wall. Intracystic eosinophilic secretion. Solitary cholesterol granulomas and focal calcifications. No signs of malignancy.
Cystic nephroma with focal regressive changes.
Cystic nephroma
Dr Mohamed Saber and Assoc Prof Frank Gaillard◉◈ et al.
Cystic nephromas, previously known as multilocular cystic nephromas, are rare benign renal neoplasms classically occurring in adult females in the 4th and 5th decades. As of the 2016 WHO classification, they are considered distinct from paediatric cystic nephromas which have associated DICER1 gene mutation 10,11,14.
Terminology
Evolving terminology regarding cystic nephromas and other cystic renal tumours reflects ongoing changes in classification, in step with shifting understanding of the disease processes and genetic aberrations.
Classically, cystic nephromas were thought to occur in a bimodal age distribution, affecting young children and adults in middle age and the generic term “multilocular cystic renal tumour” was sometimes used.
Lesions arising in children are distinct from adult cystic nephromas on both immunohistochemical and genetic bases, and are separately categorised by WHO 10,11,14
cystic nephroma (adult)
paediatric cystic nephroma (paediatric)
cystic partially differentiated nephroblastoma (paediatric)
As of 2016, the WHO classifies cystic nephroma within the mixed epithelial and stromal tumour (MEST) family along a spectrum of disease 10,13,14. The remainder of this article will discuss the adult form of cystic nephroma.
Epidemiology
overall rare
adult (typically in the 5th - 6th decades)
females are predominantly affected
Clinical presentation
abdominal pain 12
palpable abdominal mass 12
asymptomatic - incidentally discovered on imaging
Pathology
Grossly, multilocular cystic renal tumours are typically unifocal multiloculated cystic masses surrounded by a thick fibrous capsule and compressed parenchyma 8. Calcification, haemorrhage, and necrosis are unusual.
Microscopically, these tumours are lined by flat, cuboid, or hobnail cells 8, while the fibrous septa may contain mature tubules 3.
Radiographic features
Multilocular cystic renal tumours generally have the appearance of a multilocular cystic encapsulated mass on most modalities.
Plain radiograph
May present as a large abdominal mass displacing and effacing adjacent bowel loops.
Ultrasound
multilocular cystic mass originating from kidney 4
claw or beak-shape of adjacent renal parenchyma (claw sign) may help confirm a renal origin
cyst contents usually anechoic, but low-level echoes may be seen
septal vascularity can also be seen 8
CT
multilocular cystic mass often herniates into the renal pelvis
variable septal enhancement
no nodular or solid enhancement 8
+/- associated streakiness in perirenal fat 4
MRI
Signal characteristics include:
T1: variable signal, depending on the protein or blood products of the cysts
T2: hyperintense (cysts)
T1 C+ (Gd): septal enhancement may be seen
Treatment and prognosis
Radical or partial nephrectomy is usually done, with lymph node excision.
Differential diagnosis
Cystic nephroma is indistinguishable from multilocular cystic renal neoplasm of low malignant potential, formerly multilocular cystic renal cell carcinoma 15.
See also
WHO classification of tumours of the kidney
Crack the Core p231
- non-communicating fluid filled locules surrounded by a thick fibrous capsule
- by definition these things are characterized by the absence of a solid component or necrosis
- BUZZWORD = protrudes into the renal pelvis
- The question is likely the bimodal occrence
- 4 yo boys
- 40 yo women
- The Michael Jackson lesion: loves little boys and middle aged women.
6 ddx of
Dilated Tubes
(Hydrosalpinx, Pyosalpinx, Hematosalpinx)
Dilated Tubes (Hydrosalpinx, Pyosalpinx, Hematosalpinx)
- Infection
- Tumor:
- endometrial
- tubal carcinoma
- Endometriosis
- Iatrogenic ligation
14 ddx of Bladder Filling defect
3 categories
Bladder Filling Defect
- Tumor
- Primary: TCC, SCC
- Metastases
- Endometriosis
- Polyps
- Infection
- PID
- Parasitic infection: schistosomiasis
- Related to infection:
- Leukoplakia
- malacoplakia
- Cystitis cystica
- cystitis glandularis
- Luminal
- Calculi
- Blood clot
- Foreign bodies
- BPH
7 DDx of Hyperechoic renal mass
Hyperechoic Renal Mass
- AML
- RCC (the larger, the more likely to be hyperechoic)
- Milk of calcium cyst
- Nephritis
- XGP
- Emphysematous pyelonephritis
- Focal nephritis
- Candidiasis
- Hematoma
- Infarction
- Lesions that mimic true hyperechoic masses
- Renal sinus fat
- Duplicated collecting system
13 DDx of cystic renal masses
3 categories
Cystic Renal Masses
- Tumors
- Cystic/necrotic RCC
- Multilocular RCC
- Cystic Wilms tumor
- True cysts
- Cortical cysts
- Localized cystic disease
- MCD
- APKD
- Cysts in systemic disease
- VHL
- tuberous sclerosis
- End-stage renal failure
- Infectious cysts
- Other (use Doppler or color US for differentiation)
- Hydronephrosis/duplicated system
- Renal artery aneurysm
- Abscess
What are the causes of Thickened endometrial Stripe?
4 pregnancy related
4 post menopausal
- Pregnancy Related:
- Normal early pregnancy
- Ectopic
- Incomplete abortion
- Molar pregnancy
- cystic spaces can be missing early on
- Post Menopausal:
- hyperplasia
- Tamoxifen, estrogen replacement
- Polyps
- Endometrial cancer
MNEMONIC
Ddx for Papilary Necrosis
Papillary Necrosis ( Fig. 4.55 )
Mnemonic: POSTCARD :
- P yelonephritis
- O bstruction (chronic)
- S ickle cell disease
- T B
- C irrhosis, ethanol
- A nalgesics: phenacetin
- R VT (renal vein thrombosis)
- D iabetes
10 Ddx of Medially Deviated Ureters
Medial Deviation
- Posterior bladder diverticulum (most common cause of distal medial deviation)
- Uterine fibroids
- Retroperitoneal fibrosis; associated with:
- Aortic aneurysm: chronic leakage?
- Methysergide/ergots
- Idiopathic
- Malignancy-related
- Postoperative (node dissection)
- Enlarged prostate (J-shaped ureter)
- Retrocaval ureter (only on right side)
15 ddx of Solid Testicular Mass
5 categories
Solid Testicular Masses
- Tumor
- Primary
- germinal, 95%;
- nongerminal, 5%
- Metastases:
- prostate
- kidney
- leukemia
- lymphoma
- Primary
- Infection
- Orchitis
- Abscess
- Granuloma
- Trauma
- fracture
- rupture
- hemorrhage
- torsion
- Atrophy
- Dilated rete testes
Hypoechoic Structures in Hyperechoic Endometrium
Premenopausal 4 Ddx
Postmenopausal 3 Ddx
- Premenopausal
- Molar pregnancy
- Retained placenta, abortus
- Degenerated placenta
- Degenerated fibroid
- Postmenopausal
- Cystic glandular hyperplasia
- Endometrial polyps
- Endometrial carcinoma
5 Ddx of Bladder Calculi causes
Bladder Calculi
- Chronic bacterial infection, 30%
- Chronic bladder catheterization (struvite stones)
- Bladder outlet obstruction, 70%
- Schistosomiasis
- Renal calculi (usually pass through urethra)
cortical nephrocalcinosis
- cortical necrosis
- disseminated PCP
Autosomal dominant polycystic kidney disease
Dr Mohamed Saber and Assoc Prof Frank Gaillard◉◈ et al.
Autosomal dominant polycystic kidney disease (ADPKD), also sometimes more vaguely referred to as “adult polycystic kidney disease”, is as the name would suggest, a hereditary form of adult cystic renal disease.
Epidemiology
Autosomal dominant polycystic kidney disease is one of the most common serious hereditary diseases, found in 1:400 to 1:1000 individuals, and by far the most common hereditary cause of end stage renal failure (ESRF) 6. It accounts for 4-10% of all cases of ESRF 6.
Clinical presentation
The kidneys are normal at birth, and with time develop multiple cysts. At the age of 30 years, approximately 68% of patients will have visible cysts by ultrasound 3. That figure increases over time, such that essentially all patients eventually demonstrate cystic change. By the age of 60 years, approximately 50% of patients have end stage renal failure. The risk of renal cancer is not increased.
Clinical presentation is variable and includes 1:
dull flank pain of variable severity and time course: most common
abdominal or flank masses
haematuria
hypertension: usually develops at the same time as renal failure
renal functional impairment to renal failure
Pathology
Macroscopically the kidney demonstrates a large number of cysts of variable size (from a few mm to many cms), in both the cortex and medulla. They are filled with fluid of variable colour (from clear or straw coloured to altered blood or chocolate coloured to purulent when infected).
Associations
A number of conditions are well recognised as being associated with ADPKD 1,3,5,6:
cerebral berry aneurysms
found in 6% of patients with ADPKD without a family history of aneurysms
found in up to 16% of patients with ADPKD with a family history 4
intracranial dolichoectasia: 2-3% 6
hypertension: up to 80% adults 6
colonic diverticulosis
small bowel diverticula (perhaps) 5
bicuspid aortic valve
mitral valve prolapse: up to 25% 3
aortic dissection
multiple biliary hamartomas (von Meyenberg complexes) 9
cysts in other organs
liver: most common, 75% by age 60 years 6
ovaries
spleen: ~5 %
seminal vesicles: 60% by age 40 years 6
prostate: 11%
pancreas: ~10%: N.B. pancreatic cysts are more common in von Hippel Lindau disease (vHL)
Genetics
The majority of cases are inherited in an autosomal dominant fashion. In a minority of cases, no family history is present, and the disease is due to a spontaneous mutation 1.
Two genes have been identified, with slightly different phenotypes 1,3:
PKD1
located on chromosome 16p
85% of cases
presentation is earlier and more likely to progress to end stage renal failure (ESRF)
PKD2
located on chromosome 4q
15% of cases
less severe
A third rare type of ADPKD (termed ADPKD 3) has been described, however, the gene has yet to be identified 3.
The defect results in cystic dilatation of the renal tubules (of all parts of the nephron) in a minority of nephrons. The cysts are variable in size and result in compression of the remainder of the kidney, resulting in increased renin and erythropoietin secretion, and gradual renal dysfunction.
Radiographic features
Imaging of patients with autosomal dominant polycystic kidney disease can be challenging, simply due to the size and number of the cysts and associated mass effect on adjacent structures. It is potentially tedious, but necessary, to assess all cysts for atypical features, that may reflect complications (e.g. haemorrhage or infection) or malignancy (i.e. renal cell carcinoma) 2.
Plain radiograph
Plain films have no role in the surveillance of patients with established ADPKD. The diagnosis may be suspected when the renal outlines are enlarged, multilobulated or difficult to discern, with associated displacement of loops of bowel.
Multiple calcifications may be seen which may have multiple ring configurations.
On intravenous urography, “Swiss cheese nephrogram” is seen due to multiple radiolucencies noted as a result of multiple renal cysts. “Spiderleg pyelogram” is also described since stretched out and attenuated pelvicalyceal system is seen as a result of mass effect caused by renal cysts.
Ultrasound
Ultrasound is an excellent choice for repeated imaging as it is fast, relatively inexpensive and lacks ionising radiation. It is able both to suggest the diagnosis and to assess for cyst complications.
Simple renal cysts will appear anechoic with well-defined imperceptible walls, posterior acoustic enhancement (amplification) and lateral shadowing (extinction) 3.
Cysts with haemorrhage or infection will demonstrate echogenic material within the cyst, without internal blood flow. Calcification may develop. Renal cell carcinomas in contrast, although usually cystic in the setting of ADPKD, will have solid components of thick septa with blood flow.
Perinephric haematomas may be visible and collections of variable echogenicity surrounding the kidney.
Additionally, ultrasound is also able to visualise cysts in other abdominal organs.
CT
CT is of course very sensitive to the diagnosis and excellent at characterising renal cysts. Simple cysts appear as rounded structures with near water attenuation (~ 0 HU). The wall is very thin and regular, and are often imperceptible.
Cysts which have had internal complications may be hyperattenuating, with internal non-enhancing septations and/or calcifications.
A complex cystic mass with solid components or thick septa which enhance should be viewed with suspicion, and presence of a renal cell carcinoma (RCC) suspected (see Bosniak classification of renal cysts).
MRI
Renal cysts appear morphologically the same as on CT, rounded well-defined structures with very thin regular walls 8.
T1: low signal
T2: high signal
T1 C+ (Gd)
although MRI has exquisite contrast resolution, care must be taken prior to administering gadolinium-based contrast agents due to the risk of nephrogenic systemic fibrosis
simple cysts should not have any solid enhancing components
presence of enhancement of a solid component or septa should raise the possibility of a renal cell carcinoma (RCC) (N.B. infected cysts may peripherally enhance, as do islands of trapped renal tissue)
Treatment and prognosis
ESRF requiring transplant or dialysis eventually develops in many patients (45% by the age of 60). Patients with PKD1 mutations are more likely to progress to ESRF and often do so at an earlier age 1.
Complications
Complications may be both local (i.e. of the kidney) or of other organ systems.
Renal complications include 1,3:
progression to end stage renal failure
recurrent urinary tract infections
cyst haemorrhage or infection-resulting in acute pain
cyst rupture: resulting in retroperitoneal haemorrhage
Unlike in some other congenital cystic kidney diseases, there is no increased risk for renal cell carcinoma (RCC) unless the patient is undergoing prolonged dialysis 11.
Distant complications include:
subarachnoid haemorrhage
aortic dissection
Differential diagnosis
General imaging differential considerations include:
von Hippel Lindau disease (vHL)
pancreatic cysts more common
primary renal disease related cysts
the renal parenchyma appears abnormal, reduced in volume with increased echogenicity on ultrasound 3
multiple ‘incidental’ renal cysts
usually far fewer in number
kidney not enlarged
hydronephrosis mimicking multiple cysts
acquired cystic kidney disease: occurs in those with chronic renal failure (particularly in those on dialysis)
autosomal recessive polycystic kidney disease (ARPKD)
enlarged kidney
cysts are very numerous and small
changes are present in childhood
corticomedullary differentiation is lost
medullary cystic disease
cysts smaller and located in the medulla cortex junction 7
multicystic dysplastic kidney
may be unilateral, unlike ADPKD
Practical points
it is often useful for the nephrologist if the radiologist provides the total kidney volume (TKV) for both kidneys
one of the most common TKV calculators in use (the Mayo calculator) relies on four different measurements: an AP measurement, a TRV measurement, a long axis measurement in the sagittal plane, and a long axis measurement in the coronal plane
Approach in postmenopausal patient with vaginal bleeding:
EMS ≤2 m
EMS <4 m
EMS ≥5 mm
Approach in postmenopausal patient without vaginal bleeding:
EMS ≥8 m
Endometrial cancer may be indistinguishable from other benign causes of thickened EMS; therefore curettage is indicated in postmenopausal patient.
A sonographically normal endometrium in a postmenopausal woman excludes significant pathology.
Approach in postmenopausal patient with vaginal bleeding:
EMS ≤2 mm: endometrial atrophy
EMS <4 mm: no further workup
EMS ≥5 mm: endometrial sampling
Approach in postmenopausal patient without vaginal bleeding:
EMS ≥8 mm: sonohysterogram to characterize
Staghorn
Staghorn and Related Signs
A renal stone described as a staghorn implies a branched renal calculus that resembles the antlers of a stag (,,,Fig 1). It is usually composed of struvite; but less commonly, it is formed from cystine or uric acid. In its most common form, a staghorn renal stone is associated with recurrent urinary tract infections from bacterial pathogens that produce alkaline urine. As such, it is the only type of renal stone that is more commonly seen in women (,1).
The staghorn configuration can be disrupted when infection complicates obstruction related to the stone. Renal enlargement from pyonephrosis or xanthogranulomatous pyelonephritis may produce a fragmented staghorn (,2). In addition to the obstructing stone, which may be fragmented, renal enlargement and nonexcretion of contrast material from the involved kidney constitute the classic excretory urographic triad of xanthogranulomatous pyelonephritis (,,,Fig 2). A stone associated with a nonfunctioning kidney may also be seen with pyonephrosis or long-standing hydronephrosis. CT of xanthogranulomatous pyelonephritis will also illustrate this classic triad. The replacement of the renal parenchyma by the indolent infectious process in the diffuse form of xanthogranulomatous pyelonephritis produces hypoattenuating masses arranged in a “hydronephrotic” pattern, which replaces the renal parenchyma. There may be enhancement in the margins of these masses after contrast material administration. This appearance on CT scans has been described as the bear pawsign (,,,,Fig 3) (,3).
https://pubs.rsna.org/doi/10.1148/rg.24si045509#F1A
8 ddx of Solid ovarian mass lesions
4 categories
Solid Ovarian Mass Lesions
- Benign tumor:
- fibroma,
- thecoma,
- endometrioma
- germ cell tumor
- Malignant ovarian tumors
- Metastasis
- Masses simulating ovarian tumor
- Pedunculated fibroid
- Lymphadenopathy
3 ddx for Epididymal Mass
Epididymal Mass
- Focal epididymitis
- Adenomatoid tumor
- Embryonal rhabdomyosarcoma in children
Which type of RCC can have fat in it?
- Clear cell
- leads to the potential sneak situation of a fat containing lesion in the liver (which can be a RCC met)
- RCCs with macroscopic fat nearly always have some calcs/ossification. If they don’t its probably an AML.
6 Ddx of Laterally Deviated Ureters
Deviated Ureters
Normal ureters project over the transverse processes of the vertebral bodies. Deviations occur laterally or medially.
Lateral Deviation
- Bulky retroperitoneal adenopathy
- Primary retroperitoneal tumors
- Aortic aneurysm
- Retroperitoneal fluid collection
- Malrotated kidney
- Ovarian/uterine masses
are uric acid renal stones invariably a/w hyeruricaemia?
- Robbins
- Etiology and Pathogenesis (p. 951)
Increased concentrations of stone constituents, changes in urinary pH, decreased urine volume, and bacteria all play a role in stone formation. In addition, loss of inhibitors of crystal formation (e.g., citrate, pyrophosphate, glycosaminoglycans, osteopontin, and a glycoprotein called nephrocalcin) can also contribute.
There are four types of calculi; all also contain an organic matrix of mucoprotein (1% to 5% by weight):
•
Approximately 70% are calcium-containing stones composed of calcium oxalate and/or calcium phosphate. These are usually associated with hypercalcemia or hypercalciuria (60%); hyperoxaluria and hyperuricosuria are contributory in others, and in 15% to 20%, there is no demonstrable metabolic abnormality.
•
Approximately 5% to 10% of calculi are triple phosphate or struvite stones composed of magnesium ammonium phosphate. Struvite stones precipitate in alkaline urine generated by bacterial infections that convert urea to ammonia (e.g., Proteus). Staghorn calculi—occupying large parts of the renal pelvis—are struvite stones usually associated with infections.
•
Approximately 5% to 10% are uric acid stones; more than half of such patients are neither hyperuricemic nor hyperuricosuric and instead make exceptionally acidic urine (pH < 5.5) that causes uric acid to precipitate.
•
Between 1% and 2% of calculi are composed of cystine and are caused by genetic defects in renal amino acid resorption.
3 casues of Shadowing Structures in Endometrial Cavity (US)
Shadowing Structures in Endometrial Cavity (US)
- IUD
- Calcifications: fibroids, TB
- Pyometra (gas)
Steinstrasse
Case courtesy of Dr Roberto Schubert, Radiopaedia.org, rID: 17305
Steinstrasse [stīn′shtra-se] is the German word for “stone street”, describing a possible complication of extracorporeal shock wave lithotripsy (ESWL) for urinary tract calculi, wherein a column of stone fragments forms that blocks the ureter.
https://radiopaedia.org/articles/steinstrasse
Incidence
Steinstrasse usually develops 1 day to 3 months after stone fragmentation by extracorporeal shock wave lithotripsy (ESWL). The most common site of the column of stone fragments obstruction is the distal ureter (64%), followed by proximal ureter (29%), and mid ureter (8%) 2.
These days, refined extracorporeal shock wave lithotripsy technique has reduced the incidence of steinstrasse from 20% to 6% 2.
Treatment and Prognosis
Usually, the stone fragments pass spontaneously, but in about 25% of patients, retrograde stenting may be required to release the ureteral obstruction until the stone fragments become displaced and pass.
In rare cases, more complex interventions such as stone flushing, ureteral dilatation, or long-term ureteral stenting may be required 3.
Case courtesy of Dr Maulik S Patel, Radiopaedia.org, rID: 9834
When reporting a femal pevlic US, what thing do you need to think about in:
Premenopausal woman
Post Menopausal woman
Premenopausal woman: ?Pregnancy
Post Menopausal woman: ? Estrogens
medullary nephrocalcinosis
- hyperparathyroidism
- medullary sponge kidney - unilateral, less dense calcs
- lasix (children)
- RTA type 1 (distal)
7 DDx of Uterine Enlargement or Distortion
Uterine Enlargement or Distortion
- Fibroids (most common cause)
- Adenomyosis
- Less common causes
- Congenital uterine anomalies
- Inflammation: PID, surgery
- Endometriosis
- Malignant tumors
Four subtypes of RCC
- Clear Cell
- most common subtype in the Gen pop.
- A/W VHL
- more aggressive than Papillary.
- Enhances = to cortexon the corticomedullary phase
- Classically a cystic mass with enhancing components
- Papillary
- 2nd most common
- less aggressive than clear cell
- less vascular and will not enhance = to cortex on CM phase.
- Classically T2 dark (ddx lipid poor AML and hemorrhagic cyst)
- A/w renal transplant
- risk of primary rental malig in a tx kid is six times that of normal.
- Medullary
- A/W Sickle Cell Train
- HIGHLY agressive
- urually large
- usually has mets already by time of dx
- patients are usually yonger
- Chromophobe
- Birt-hog-dube
Crack the core p229
Transitional cell carcinoma (urinary bladder)
https://radiopaedia.org/articles/transitional-cell-carcinoma-urinary-bladder
Dr Tom Foster◉ and Assoc Prof Frank Gaillard◉◈ et al.
Transitional cell carcinoma (TCC), also called urothelial cell carcinoma (UCC) of the bladder, is the most common primary neoplasm of the urinary bladder, and bladder TCC is the most common tumor of the entire urinary system.
This article concerns itself with transitional cell carcinomas of the bladder specifically. Related articles include:
general discussion: transitional cell carcinoma of the urinary tract
TCCs in other locations:
transitional cell carcinoma of the renal pelvis
transitional cell carcinoma of the ureter
transitional cell carcinoma of the urethra
other histologies:
squamous cell carcinoma of the bladder
adenocarcinoma of the bladder
7 Ddx of Adrenal Cystic Masses
Cystic Masses
- Lymphangioma
- Hemangioma
- Epithelial cyst
- Adenom
- pheochromocytoma
- metastasis
- Hemorrhage
5 Ddx of Dilated Calyces/Collecting System
Dilated Calyces/Collecting System ( Fig. 4.57 )
- Obstruction (calculi, tumor, acute, chronic)
- Papillary necrosis
- Congenital megacalyces
- Calyceal diverticulum
- Reflux
Associations
Males or females more common
Usual composition?
>I staghorn calculus:
= branched calculus filling the entire bifid renal collecting
system
Composition: struvite (=mixture of calcium,
magnesium, ammonium, phosphate) I
cystine I uric acid stone
- forms with recurrent urinary tract infections (the only
stone more common in females)
DAHNERT
Staghorn calculus (kidney)
Dr Yusra Sheikh◉ and Assoc Prof Frank Gaillard◉◈ et al.
Staghorn calculi, also sometimes called coral calculi, are renal calculi that obtain their characteristic shape by forming a cast of the renal pelvis and calyces, thus resembling the horns of a stag. They refers to struvite calculus involving the renal pelvis and extending into atleast two calyces7.
For a general discussion of renal calculi please refer to nephrolithiasis.
Epidemiology
Staghorn calculi are the result of recurrent infection and are thus more commonly encountered in women 6, those with renal tract anomalies, reflux, spinal cord injuries, neurogenic bladder or ileal ureteral diversion.
Clinical presentation
The majority of staghorn calculi are symptomatic, presenting with fever, haematuria, flank pain and potentially septicaemia and abscess formation.
Pathology
Staghorn calculi are composed of struvite (chemically this is magnesium ammonium phosphate or MAP) and are usually seen in the setting of recurrent urinary tract infection with urease-producing bacteria (e.g. Proteus, Klebsiella, Pseudomonas and Enterobacter). Urease hydrolyses urea to ammonium with an increase in the urinary pH 3-5.
Struvite accounts for approximately 70% of the composition of these calculi and is usually mixed with calcium phosphate thus rendering them radiopaque on both plain films and CT. Uric acid and cystine are the underlying components of a minority of these calculi 5.
Radiographic features
Plain radiograph
The vast majority of staghorn calculi are radiopaque and appear as branching calcific densities overlying the renal outline and may mimic an excretory phase intravenous pyelogram. Lamination within the stone is common.
Ultrasound
The collecting system is filled with a densely calcified mass, producing marked posterior acoustic shadowing.
CT
Staghorn calculi are radiopaque and conform to the renal pelvis and calyces, which are often to some degree dilated. When viewed on bone windows they have a laminated appearance, due to alternating bands of magnesium ammonium phosphate and calcium phosphate 5.
Treatment and prognosis
Staghorn calculi need to be treated surgically, usually PCNL (percutaneous nephrolithotomy) +/- ESWL (extracorporeal shockwave lithotripsy) and the entire stone removed, including small fragments, as otherwise, these residual fragments act as a reservoir for infection and recurrent stone formation.
If left untreated, staghorn calculi result in chronic infection and eventually may progress to xanthogranulomatous pyelonephritis 5.
Differential diagnosis
There is usually little differential, provided intravenous contrast has not been administered. In the latter situation, the opaque collecting system may be attributed to contrast rather than the calculus, especially when staghorn calculi are bilateral.
7 Ddx of Multiple Ureteral Filling Defects
of the Wall
Wall Multiple Ureteral Filling Defects
- Ureteritis cystica (more common in upper ureter)
- Allergic mucosal bullae
- Pseudodiverticulosis
- Vascular impressions (collateral veins in IVC obstruction)
- Multiple papillomas (more common in lower ureter)
- Melanoma metastases
- Suburothelial hemorrhage (less discrete than ureteritis cystica and associated with a coagulopathy)
8 DDx of Extracalyceal Contrast Agent
Extracalyceal Contrast Agent ( Fig. 4.56 )
- Striations
- Medullary sponge kidney
- Early papillary necrosis
- Pyelosinus or pyelovenous backflow in obstruction
- Interstitial edema
- Focal collections
- Late papillary necrosis
- Calyceal diverticulum
- Cavity from cyst rupture
- Abscess
multiple bilateral hypodense or infiltrative renal masses
dx?
Crack the core p 230
- renal lymphoma
- can look like anything
- bilaterally enlarged kidneys with small low attenuation corticlaly based solid nodules or masses
- infiltrative soft tissue int he renal hilum
- A/w LAD
- 25% will be a solitary mass.
- Out of all the real masses lymphoma is the most likely to preserve thenormal reniform shape
- lymphoma is the ost common metastatic tumour to invade/infiltrate the kidneys
Renal lymphoma
Dr Mohamed Saber and Dr Praveen Jha et al.
Renal lymphoma is usually a part component of multi-systemic lymphoma. Primary renal lymphoma, which is defined as lymphoma involving the kidney exclusively without any manifestation of extra-renal lymphatic disease 3-5. Typical imaging findings are multiple bilateral hypodense or infiltrative renal masses.
Epidemiology
While renal lymphoma has an autopsy incidence of ~45% (range 30-60%) in lymphoma patients, the incidence by CT evaluation is ~5% 1.
The kidneys are the most common abdominal organ affected by lymphoma. Most instances are B-cell non-Hodgkin lymphoma; primary renal lymphoma is rare (<1%). Involvement of kidneys in Hodgkin lymphoma is rare (<1%).
Primary renal lymphoma more frequently affects the middle-aged men 5. Patients with organ transplantation (immunosuppression) and the patients with HIV infection (immunocompromised) are prone to develop renal lymphoma 3,5.
Clinical presentation
Patients present with flank pain (the commonest symptom), weight loss, haematuria, or a palpable mass. Acute renal failure may be seen in infiltrative disease.
Abdominal/flank pain (62%) is the commonest symptom in adult patients (18-50 years), fever (56%) is the commonest symptom in younger patients (<18 years) and weight loss and haematuria (37%) are the common symptoms in the older patients (> 50 years) 4.
Pathology
The exact cause or origin of primary renal lymphoma is controversial, as the kidney is an extranodal organ and is devoid of lymphoid tissue normally. It is hypothesised that primary renal lymphoma likely arises from the capsule of the kidney or peri-renal fat (lymphoid rich tissues) and afterwards involves the renal parenchyma. The lymphocytes seen in the region of chronic renal inflammation have also been proposed as a potential causative factor 3-5.
Renal lymphoma occurs commonly with non-Hodgkin lymphoma. The majority have intermediate or high-grade lymphomas including Burkitt and histiocytic varieties 2. Most are B-cell lymphoma.
On gross examination, lesions are fleshy or firm yellow, tan, or grey tumours of 1-20 cm size.
Associations
immunodeficiency (e.g. HIV)
ataxia-telangiectasia
Radiological features
Fluoroscopy
It is the most sensitive imaging for the involvement of the renal collecting system and ureters, as well as provides functional information.
Ultrasound
Hypoechoic lesions (single/multiple) within renal parenchyma with very little internal vascularity.
CT
CT is the imaging modality of choice 3. The following patterns of disease may be seen on CT:
multiple masses (up to 60%: most common pattern)
typically 1-3 cm in size
associated with enlarged retroperitoneal nodes (≥50%)
single mass (over 20% of cases)
up to 15 cm
homogeneous, hypodense without cystic change
calcium, bleed, or necrosis
invasion from retroperitoneal nodal mass (over 30% of cases)
usually >10 cm
encasement of vessels without thrombosis, +/- hydronephrosis
diffuse infiltration (up to 20% of cases)
no discrete mass
usually bilateral
seen with Burkitt lymphoma
perirenal mass (less than 10% of cases)
perirenal stranding
thickening of Gerota fascia
perirenal nodules
atypical patterns:
spontaneous haemorrhage
necrosis
heterogenous lesion
cystic changes
calcification
MRI
Signal characteristics
T1: hypointense to renal parenchyma
T2: iso or hyperintense to renal parenchyma
T1C+
poor enhancement compared to renal parenchyma
delayed enhancement is seen in some lesions
diffusion-weighted imaging (DWI): restricted diffusion 3-5
Nuclear medicine
PET-CT
Renal lymphoma shows intense 18F-FDG uptake. PET-CT is useful in the diagnosis of the disease, in assessing response to the therapy and in the detection of recurrent disease 3-5.
Treatment and prognosis
Chemotherapy is the mainstay of treatment 4. The prognosis of primary renal lymphoma is largely unknown. The 5-year survival rate is ~45%. Younger patients and bilateral primary renal lymphomas are associated with a poorer prognosis (shorter survival time and more rapid progression) 4.
Differential diagnosis
Imaging differential considerations include:
renal cell carcinoma: usually heterogeneous, with vascular invasion
metastases to kidney
transitional cell carcinoma
acute pyelonephritis
xanthogranulomatous pyelonephritis
retroperitoneal fibrosis
4 Ddx for Unilateral papillary necrosis
3 Ddx for Bilateral papillary necrosis
Unilateral:
- Pyelonephritis
- Obstruction
- TB
- RVT
Bilateral:
- Sickle cell disease
- Cirrhosis, ethanol
- Diabetes
12 DDx of Fluid in Uterine Cavity
3 categories
Fluid in Uterine Cavity ( Fig. 4.66 )
- Acquired (cervical stenosis)
- Tumors:
- cervical cancer,
- endometrial cancer
- Inflammatory:
- endometritis,
- PID,
- radiation
- Tumors:
- Pregnancy related
- Early IUP
- Pseudogestational sac
- Blighted ovum
- Congenital
- Imperforate hymen
- Vaginal septum
- Vaginal atresia
- Rudimentary uterine horn
Renal stones that are oxalate %?
30%
percent of people with hypercalcaemia who have renal stones
Approximately 70% are calcium-containing stones composed of calcium oxalate and/or calcium phosphate. These are usually associated with hypercalcemia or hypercalciuria (60%); hyperoxaluria and hyperuricosuria are contributory in others, and in 15% to 20%, there is no demonstrable metabolic abnormality. (Robins)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2556488/
Conclusion
Although kidney stone formation due to hypercalcemic states is rare, it is important for urologists to understand the pathophysiology of these conditions, methods of diagnosis, and treatments. This should foster a quicker diagnosis and institution of appropriate therapy. The latter typically leads to the attenuation of kidney stone activity. Moreover, these patients have a systemic disease, and therapy has other health benefits.
Main Points
The majority of patients with nephrolithiasis have calcium-containing stones. A significant number of such stone formers have increased urinary calcium excretion, but a minority has a systemic disease causing chronic hypercalcemia and promotion of stone formation.
Calcium homeostasis is normally under very tight control. A complex interplay between parathyroid hormone and calcitriol and the mineral ions maintains calcium levels within a narrow range. Calcium regulation can go awry at many different steps in the control mechanisms, but only rarely does this lead to nephrolithiasis.
Of the diseases/conditions that result in hypercalcemia and hypercalciuria and that may be associated with stone formation, the 2 most prevalent are hyperparathyroidism and sarcoidosis. Others include other granulomatous diseases (eg, leprosy, coccidioidomycosis, tuberculosis, plasma cell granuloma, Wegener’s granulomatosis, and silicosis), prolonged immobilization, milkalkali syndrome, hypervitaminosis D, and (rarely) malignancy.
Although only a small percentage of patients with stones have primary hyperparathyroidism, screening for hyperparathyroidism is still recommended. Screening with serum calcium testing is inexpensive, and when the diagnosis is established the disease can be surgically cured and stone activity significantly reduced.
Hypercalcemia due to sarcoidosis can be treated effectively with corticosteroid administration. In adults, the administration of 20 to 40 mg of prednisone daily leads to reduction in serum calcium and calcitriol and resolution of hypercalciuria, typically in 5 to 7 days.
DAHNERT p1004
UROLITHIASIS
NEPHROLITHIASIS
0 Most common cause of calcification within the kidney:
0 12% of population develop a renal stone by age 70
0 2-3% of population experience an attack of acute renal
colic during their lifetime
0 Patients with acute flank pain have ureteral calculi in
67-95%
Annual incidence: 1-2-:-1,000
Age: 30-60 years; M-:-F = 4-:-1
Anderson-Carr-Randall theory of renal stone formation :
in the presence of abnormally high calcium excretion
exceeding lymphatic capacity, microaggregates of calcium
(present in the normal kidney) occur in medulla, increase in
size, migrate toward calyceal epithelium, and rupture into
calyces to form calculi
(a) nucleation theory
= crystal I foreign body initiates formation in urine
supersaturated with crystallizing salt
(b) stone matrix theory
= organic matrix of urinary proteins + serum serves as
framework for deposition of crystals
(c) inhibitor theory
= little I no concentration of urinary stone inhibitors
(citrate, pyrophosphate, glycosam i noglycan,
nephrocalcin, Tamm-Horsfall protein) results in crystal
formation
Composition:
calcium oxalate . .. . .. . 75%
struvite . . . .. . .. . . … 15%
calcium phosphate . . … 5%
uric acid . .. . .. . .. . … 5%
cystine .. . .. . .. . …… 1%
Cause:
genetics, diet, employment, geography, history of urinary
tract infection
0 70-80% of patients with first-time stones have a specific
metabolic disorder (idiopathic hypercalciuria, secondary
hypercalciuria (sarcoidosis, hyperparathyroidism),
hyperuricosuria (gout, Lesch-Nyhan syndrome,
hyperoxaluria, cystinuria)
1. Hypercalciuria
• with hypercalcemia (50%):
primary hyperparathyroidism, milk-alkali syndrome,
hypervitaminosis D, malignant neoplasm, Paget
disease, prolonged immobilization, sarcoidosis,
adrenal insufficiency, hyper- and hypothyroidism, renal
transplantation
• with normocalcemia (30-60%):
obstruction, urinary tract infection, vesical diverticulum,
horseshoe kidney, medullary sponge kidney, renal
tubular acidosis, malignant neoplasm, Paget disease,
Cushing syndrome, prolonged immobilization, idiopathic
hypercalciuria, acetazolamide therapy, sarcoidosis
(a) absorptive hypercalciuria
= increased intestinal absorption of calcium
Cause: increase in 1,25-dihydroxy-vitamin D levels
(50%)
(b) renal hypercalciuria
= abnormal renal calcium leak
Cause: diet high in sodium, urinary tract infection
(33%)
(c) resorptive hypercalciuria
= increased bone demineralization secondary to subtle
hyperparathyroidism
(d) idiopathic
-Y attenuation of calcium stones > 1,000 HU similar to
bone cortex
5 Ddx of Multiple Ureteral Filling Defects
Luminal
Luminal Multiple Ureteral Filling Defects
- Calculi (lucent, opaque)
- Blood clot
- Sloughed papillae
- Fungus ball
- Air bubbles
ADPCKD
Autosomal dominant polycystic kidney disease
Dr Mohamed Saber and Assoc Prof Frank Gaillard◉◈ et al.
Autosomal dominant polycystic kidney disease (ADPKD), also sometimes more vaguely referred to as “adult polycystic kidney disease”, is as the name would suggest, a hereditary form of adult cystic renal disease.
Epidemiology
Autosomal dominant polycystic kidney disease is one of the most common serious hereditary diseases, found in 1:400 to 1:1000 individuals, and by far the most common hereditary cause of end stage renal failure (ESRF) 6. It accounts for 4-10% of all cases of ESRF 6.
Clinical presentation
The kidneys are normal at birth, and with time develop multiple cysts. At the age of 30 years, approximately 68% of patients will have visible cysts by ultrasound 3. That figure increases over time, such that essentially all patients eventually demonstrate cystic change. By the age of 60 years, approximately 50% of patients have end stage renal failure. The risk of renal cancer is not increased.
Clinical presentation is variable and includes 1:
dull flank pain of variable severity and time course: most common
abdominal or flank masses
haematuria
hypertension: usually develops at the same time as renal failure
renal functional impairment to renal failure
Pathology
Macroscopically the kidney demonstrates a large number of cysts of variable size (from a few mm to many cms), in both the cortex and medulla. They are filled with fluid of variable colour (from clear or straw coloured to altered blood or chocolate coloured to purulent when infected).
Associations
A number of conditions are well recognised as being associated with ADPKD 1,3,5,6:
cerebral berry aneurysms
found in 6% of patients with ADPKD without a family history of aneurysms
found in up to 16% of patients with ADPKD with a family history 4
intracranial dolichoectasia: 2-3% 6
hypertension: up to 80% adults 6
colonic diverticulosis
small bowel diverticula (perhaps) 5
bicuspid aortic valve
mitral valve prolapse: up to 25% 3
aortic dissection
multiple biliary hamartomas (von Meyenberg complexes) 9
cysts in other organs
liver: most common, 75% by age 60 years 6
ovaries
spleen: ~5 %
seminal vesicles: 60% by age 40 years 6
prostate: 11%
pancreas: ~10%: N.B. pancreatic cysts are more common in von Hippel Lindau disease (vHL)
Genetics
The majority of cases are inherited in an autosomal dominant fashion. In a minority of cases, no family history is present, and the disease is due to a spontaneous mutation 1.
Two genes have been identified, with slightly different phenotypes 1,3:
PKD1
located on chromosome 16p
85% of cases
presentation is earlier and more likely to progress to end stage renal failure (ESRF)
PKD2
located on chromosome 4q
15% of cases
less severe
A third rare type of ADPKD (termed ADPKD 3) has been described, however, the gene has yet to be identified 3.
The defect results in cystic dilatation of the renal tubules (of all parts of the nephron) in a minority of nephrons. The cysts are variable in size and result in compression of the remainder of the kidney, resulting in increased renin and erythropoietin secretion, and gradual renal dysfunction.
Radiographic features
Imaging of patients with autosomal dominant polycystic kidney disease can be challenging, simply due to the size and number of the cysts and associated mass effect on adjacent structures. It is potentially tedious, but necessary, to assess all cysts for atypical features, that may reflect complications (e.g. haemorrhage or infection) or malignancy (i.e. renal cell carcinoma) 2.
Plain radiograph
Plain films have no role in the surveillance of patients with established ADPKD. The diagnosis may be suspected when the renal outlines are enlarged, multilobulated or difficult to discern, with associated displacement of loops of bowel.
Multiple calcifications may be seen which may have multiple ring configurations.
On intravenous urography, “Swiss cheese nephrogram” is seen due to multiple radiolucencies noted as a result of multiple renal cysts. “Spiderleg pyelogram” is also described since stretched out and attenuated pelvicalyceal system is seen as a result of mass effect caused by renal cysts.
Ultrasound
Ultrasound is an excellent choice for repeated imaging as it is fast, relatively inexpensive and lacks ionising radiation. It is able both to suggest the diagnosis and to assess for cyst complications.
Simple renal cysts will appear anechoic with well-defined imperceptible walls, posterior acoustic enhancement (amplification) and lateral shadowing (extinction) 3.
Cysts with haemorrhage or infection will demonstrate echogenic material within the cyst, without internal blood flow. Calcification may develop. Renal cell carcinomas in contrast, although usually cystic in the setting of ADPKD, will have solid components of thick septa with blood flow.
Perinephric haematomas may be visible and collections of variable echogenicity surrounding the kidney.
Additionally, ultrasound is also able to visualise cysts in other abdominal organs.
CT
CT is of course very sensitive to the diagnosis and excellent at characterising renal cysts. Simple cysts appear as rounded structures with near water attenuation (~ 0 HU). The wall is very thin and regular, and are often imperceptible.
Cysts which have had internal complications may be hyperattenuating, with internal non-enhancing septations and/or calcifications.
A complex cystic mass with solid components or thick septa which enhance should be viewed with suspicion, and presence of a renal cell carcinoma (RCC) suspected (see Bosniak classification of renal cysts).
MRI
Renal cysts appear morphologically the same as on CT, rounded well-defined structures with very thin regular walls 8.
T1: low signal
T2: high signal
T1 C+ (Gd)
although MRI has exquisite contrast resolution, care must be taken prior to administering gadolinium-based contrast agents due to the risk of nephrogenic systemic fibrosis
simple cysts should not have any solid enhancing components
presence of enhancement of a solid component or septa should raise the possibility of a renal cell carcinoma (RCC) (N.B. infected cysts may peripherally enhance, as do islands of trapped renal tissue)
Treatment and prognosis
ESRF requiring transplant or dialysis eventually develops in many patients (45% by the age of 60). Patients with PKD1 mutations are more likely to progress to ESRF and often do so at an earlier age 1.
Complications
Complications may be both local (i.e. of the kidney) or of other organ systems.
Renal complications include 1,3:
progression to end stage renal failure
recurrent urinary tract infections
cyst haemorrhage or infection-resulting in acute pain
cyst rupture: resulting in retroperitoneal haemorrhage
Unlike in some other congenital cystic kidney diseases, there is no increased risk for renal cell carcinoma (RCC) unless the patient is undergoing prolonged dialysis 11.
Distant complications include:
subarachnoid haemorrhage
aortic dissection
Differential diagnosis
General imaging differential considerations include:
von Hippel Lindau disease (vHL)
pancreatic cysts more common
primary renal disease related cysts
the renal parenchyma appears abnormal, reduced in volume with increased echogenicity on ultrasound 3
multiple ‘incidental’ renal cysts
usually far fewer in number
kidney not enlarged
hydronephrosis mimicking multiple cysts
acquired cystic kidney disease: occurs in those with chronic renal failure (particularly in those on dialysis)
autosomal recessive polycystic kidney disease (ARPKD)
enlarged kidney
cysts are very numerous and small
changes are present in childhood
corticomedullary differentiation is lost
medullary cystic disease
cysts smaller and located in the medulla cortex junction 7
multicystic dysplastic kidney
may be unilateral, unlike ADPKD
Practical points
it is often useful for the nephrologist if the radiologist provides the total kidney volume (TKV) for both kidneys
one of the most common TKV calculators in use (the Mayo calculator) relies on four different measurements: an AP measurement, a TRV measurement, a long axis measurement in the sagittal plane, and a long axis measurement in the coronal plane
See also
Ciliopathy
Quiz questions
References
Related Radiopaedia articles
Renal cystic disease
Bosniak classification
simple renal cyst
polycystic disease
autosomal dominant polycystic kidney disease (ADPKD)
autosomal recessive polycystic kidney disease (ARPKD)
acquired renal cystic disease
multicystic dysplastic kidney
lithium-induced renal disease
4 Ddx of small uterus
- Small Uterus
- Hypoplasia
- Nulliparity
- Synechiae
- DES exposure
7 Ddx of Cystic Prostate lesions
Prostate
Cystic Lesions ( Fig. 4.62 )
- Utricle cyst:
- midline,
- intraprostatic,
- may communicate with posterior urethra and contain sperm
- Associated with hypospadias and cryptorchidism
- Müllerian duct cyst:
- midline,
- may rise above prostate,
- stones
- Cowper duct cyst
- Ejaculatory duct cyst
- Prostatic retention cyst
- SV cyst
- VD cyst
3 Ddx of Ureteral Diverticula
Ureteral Diverticula ( Fig. 4.59 )
- Congenital
- Ureteritis cystica
- TB (also strictures)
does proteus cause Stuvite?
yes
- Which type of tumour is most likely to protrude >50%?
- Which type of tumour is most likely to be intrarenal?
- Which type of tumor is most likely to be in the collecting system?
- Which tumour is least likely to protrude at all?
- RCC
- Renal TCC
- Renal TCC
- Renal TCC
DDx of Renal Mass/Lesion
- Tumor
- Solid
- Cyst
- Infection
- Lobar nephronia
- Abscess
- XGP
- Congenital
- Duplicated collecting system
- Pseudotumors
- Fetal lobulation
- Dromedary hump
- Column of Bertin
- Suprahilar (less commonly infrahilar) “bump”
- Lobar dysmorphism: doughnut sign on IVP or angiography
- Trauma
- Hematoma
- Crack the Core
- AML
- most common benign tuypour of the kidney
- 95% have macroscopic fat - defining feature
- usually incidental
- A/w TS/bourneville disease (case 1)
Bilateral diffuse involvement of the kidneys with multiple differential densities. The right-sided mass measures 125 x 163 mm and the left-sided mass 130 x 145 mm. Both masses have fatty components with CT density -33 HU. Contrast-enhanced scans show patchy and heterogeneous enhancement in the soft tissue and vascular component of the mass lesions. Normal excretion of contrast media was seen on both sides. Multiple areas of blood densities are noted on the right side suggesting haemorrhage. The uterus remains sub-involuted.
Case Discussion
Young female with a long history of chronic anaemia, with abnormal appearance of both kidneys discovered incidentally. CT images demonstrate bilateral giant renal angiomyolipomas. Being a common complication with giant angiomyolipomas more than 5 cm, haemorrhage may be the direct cause of the patient’s long-lasting anaemia. The patient’s renal function was within normal limits.
The patient had multiple facial angiofibromas by inspection which raises the odds of tuberous sclerosis.
- they can bleed if big enough>4cm
- ? grow/bleed more in preg
- they should never have calcifications if they do thick of RCC
- They can be lipid poor 5%. and those are T2 dark.
- case 2 = giant AML
7 Ddx of Pear/Tear Drop Shaped Bladder
Teardrop Bladder ( Fig. 4.61 )
Criteria: pear-shaped or teardrop-shaped contrast-filled bladder: secondary to circumferential extrinsic compression
- Physiologic
- Normal variant
- Iliopsoas hypertrophy
- Fluid
- Hematoma (usually from pelvic fracture)
- Abscess
- Masses
- Pelvic lymphoma
- Pelvic lipomatosis (black males, HTN)
- Retroperitoneal fibrosis
- second most common benign renal tumour after AML
- Looks a lot like an RCC
- Has a central scar 33% and 100% of the time on MCQ
- There will be no malignant features (ie vessel infiltration)
- They cannot be distinguished from an RCC on imaging
- Must be rx as an RCC till proven other wise
- solid mass with central scar
- spoke wheel vascular patten on USS
- Hotter than the surrounding renal cortex on Pet
- even if you bx it and get oncocytes, it done matter because RCCs can have concocytic appearance.
- bilaterally oncocytomas = Birt hog dube = chromophore RCC.
- PET TIP
- PCC is typically colder than surrounding renal parenchyma on PET
- Oncocytoma is typically HOTTER than surrounding Renal parenchyma on PET.
Renal oncocytoma
Dr Ian Bickle◉ and Associate Professor Donna D’Souza◉ et al.
Renal oncocytomas are relatively benign renal tumours. The main clinical importance of this lesion is the difficulty in pre-operatively distinguishing it from renal cell carcinomas, as epidemiology, presentation, imaging and even histology can be very similar.
Epidemiology
Renal oncocytomas account for approximately 5% of resected primary adult epithelial renal neoplasms. They typically present in the 6th to 7th decades with a peak incidence at 55 years of age. There is 2:1 male predilection 10,13. Unfortunately, these demographics are similar to renal cell carcinoma.
Clinical presentation
Up to three-quarters of patients with a renal oncocytoma are asymptomatic. In cases where the mass is large, then a flank or abdominal mass may be the presenting complaint. Occasionally hypertension, haematuria or pain may be the presenting complaint 13.
Pathology
Macroscopic appearance
Macroscopically oncocytomas are tan in colour, similar to the renal cortex, or darker brown (mahogany brown). A rim of compressed normal renal parenchyma is sometimes seen, forming a pseudo capsule 12,13. Macroscopic haemorrhage is seen in a minority of patients (~20%) 13.
Microscopic appearance
Oncocytomas are believed to originate from intercalated tubular cells of the collecting tubules and are composed of large, swollen eosinophilic cells of protuberant mitochondrial components 2,12,13. A biopsy is usually unhelpful in distinguishing an oncocytoma from a renal cell carcinoma, as the latter may also have oncocytic elements 9. Necrosis is usually absent 12.
Associations
Birt-Hogg-Dubé syndrome
tuberous sclerosis 8
Radiographic features
Unfortunately, the imaging appearance of oncocytomas is difficult to distinguish from renal cell carcinoma, and as such, they are usually resected 9. They appear as sharply demarcated lesions of variable size, but often large at presentation. A potentially helpful sign is the presence of a sharp central stellate scar, which although characteristic of oncocytomas, is only seen in a third of cases 4. Additionally, renal cell carcinomas may also demonstrate a central scar 9.
The only reliable feature is evidence of metastasis or aggressive infiltration into adjacent structures, in which case the diagnosis of renal cell carcinoma can be safely made.
It is important to carefully evaluate both kidneys, as up to 13% of patients have multiple oncocytomas (renal oncocytosis), and up to 32% have concurrent renal cell carcinomas 13.
Intravenous pyelogram
Oncocytomas appear as sharply demarcated, often large exophytic masses with enhancement during the nephrographic phase.
Ultrasound
Ultrasound demonstrates a well-circumscribed mass with echogenicity similar to the rest of the kidney. Occasionally a central scar may be visible 9.
CT
Tend be large well-demarcated tumours at presentation.
Non-contrast
if less than 3 cm - homogenous attenuation
if more than 3 cm - heterogeneous attenuation
perinephric fat stranding may be present due to oedema
calcification may be present
Post contrast
small tumours may enhance homogeneously, but usually enhancement is heterogeneous and the mass is larger
central stellate non-enhancing scar is seen in approximately a third of cases 4
renal vein thrombosis may be present, but tumour thrombus is absent
MRI
Typical signal characteristics include:
T1: hypointense compared to renal cortex 14
T2
hyperintense compared to renal cortex
may demonstrate hypointense central stellate scar
T1 C+ (Gd): usually demonstrates homogeneous enhancement
Angiography
May demonstrate a spoke wheel pattern, of peripheral circumferential vessels penetrating towards the centre of the lesion, which again, although characteristic of oncocytomas, may also be seen in renal cell carcinomas.
During the capillary phase, the tumour demonstrates a homogeneous blush, similar to normal renal parenchyma, lacking the ‘bizarre’ vascularity typically seen in RCCs 7,9,12. A lucent avascular rim may be seen due to the compressed pseudo capsule 12.
Microaneurysms have occasionally been reported 12.
Treatment and prognosis
Although renal oncocytomas are benign lesions and metastases are extremely uncommon 6,13, as they cannot be confidently pre-operatively distinguished from renal cell carcinomas, they are surgically resected. If the diagnosis is suspected pre-operatively then renal sparing surgery can be performed.
Differential diagnosis
General imaging differential considerations include
renal cell carcinoma (RCC)
the imaging appearances of RCCs and oncocytomas overlap to such a degree that confident pre-operative distinction is not possible
metanephric neoplasms
metanephric adenoma
metanephric adenofibroma
renal leiomyoma
Practical points
biopsy is usually unhelpful in distinguishing an oncocytoma from a renal cell carcinoma, as the latter may also have oncocytic elements
gross invasion of perirenal fat, tumoural extension into the renal vein, and regional lymphadenopathy on imaging would favour RCC instead of oncocytoma
Quiz questions
What is this sign called?
What is it a complication of?
Left renal stone is noted, with multiple small stones aligned in the lower portion of the left ureter. (Steinstrasse)
Case Discussion
Steinstrasse or stone street, describing a complication of extracorporeal shock wave lithotripsy (ESWL) for urinary tract calculi, wherein a column of stone fragments forms that blocks the ureter.
Case courtesy of Dr Mohammad Taghi Niknejad, Radiopaedia.org, rID: 63261
Case courtesy of Dr Naqibullah Foladi, Radiopaedia.org, rID: 70943
https://radiopaedia.org/articles/horseshoe-kidney
