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Ultrasound of the urinary tract - Renal tumors
1. Ultrasound of the urinary tract
Renal tumors
Samir Haffar M.D.
Department of Internal Medicine
2. Ultrasound of renal tumors
• US is often the first imaging modality of kidneys
• Plays important role in diagnosis of renal tumors
• Technical advances improved detection of renal tumors
Tissue harmonic imaging (THI)
Color Flow Doppler
Contrast-enhanced Doppler
CT is the gold standard for detection &
characterizationof renal mass lesions
7. Dromedary hump
Common renal variation
Paspulati RM et al. Ultrasound Clin 2006 ; 1 : 25 – 41.
Focal bulge on lateral border of left kidney
Result from adaptation of renal surface to adjacent spleen
Easily differentiated from renal mass: US – Doppler
8. Persistent fetal lobulation
Paspulati RM et al. Ultrasound Clin 2006 ; 1 : 25 – 41.
Renal surface indentations between pyramids
May be single or multiple
10. Prominent column of Bertin (PCB)
Mistaken for intrarenal tumor
Paspulati RM et al. Ultrasound Clin 2006 ; 1 : 25 – 41.
Continuity with renal cortex
Similar echo as renal parenchyma
Less than 3 cm in size
Contains renal pyramids
Similar vascular pattern by color Doppler
11. Prominent column of Bertin (PCB)
Medullary pyramids
seen within PCB
Sagittal sonogram
Classic appearance
Transverse sonogram
Classic appearance
Rumack CM et al. Diagnostic Ultrasound. Elsevier-Mosby, St. Louis, USA, 3rd edition, 2005.
12. Parenchymal junctional defect
Paspulati RM et al. Ultrasound Clin 2006 ; 1 : 25 – 41.
Commonly mistaken for cortical scar or angiomyolipoma
Continuity with central sinus
by echogenic line
Triangular hyperechoic structure
Antero-superior or postero-inferior
surface of kidney “interrenicular septum”
13. Hypoechoic renal sinus
Rumack CM et al. Diagnostic Ultrasound. Elsevier-Mosby, St. Louis, USA, 3rd edition, 2005.
Fat-filled hypoechoic renal sinus mimicking mass lesion
Absence of a well-defined margin
Normal vessels traversing renal sinus by CFD
15. Benign renal tumors
• Angiomyolipoma Sporadic – Associated with TS
• Adenoma Benign counterpart of RCC
Tumors < 3 cm rarely metastasize
• Oncocytoma Tumor of renal tubular origin
Differentiation from RCC difficult
Hypo, iso, or hyperechoic to cortex
• Leiomyoma Rare, peripheral or central
Solid, mixed, or cystic lesion
• Reninoma
• Hemangiopericytoma
Paspulati RM et al. Ultrasound Clin 2006 ; 1 : 25 – 41.
16. Angiomyolipoma (AML)
Hamartoma (mature adipose tissue, SM, blood vessels)
• Sporadic (80%) Middle-aged women, unilateral
Tuberous sclerosis (20%) Younger, multiple, bilateral, larger
• Grows during pregnancy & presents with hemorrhage
Retroperitoneal bleeding (Wunderlich’s syndrome):10%
Risk of rupture: > 4 cm – microaneurysms > 5 mm
• Management: observation – embolization – renal-sparing surg
Paspulati RM et al. Ultrasound Clin 2006 ; 1 : 25 – 41.
Overlap between imaging features of AML & small RCC
17. Sonography of angiomyolipoma
• Classic pattern Well-defined hyperechoic mass
Posterior acoustic shadowing
Small RCC Well-defined hyperechoic mass
Hypoechoic rim
Intratumoral cystic changes
• Hypoechoic pattern Vessels or bleeding predominate
• Hemorrhagic pattern Central – perirenal
Depends on proportion of fat, SM, vessels & bleeding
Rumack CM et al. Diagnostic Ultrasound. Elsevier-Mosby, St. Louis, USA, 3rd edition, 2005.
18. Angiomyolipoma – Classic pattern
Paspulati RM et al. Ultrasound Clin 2006 ; 1 : 25 – 41.
CT (excretory phase)
Fat attenuation lesion
Household unit of – 8
Well defined hyperechoic mass
Posterior acoustic shadowing
Longitudinal US of right kidney
Intra-tumoral fat on CT almost confirms diagnosis of AML
19. Renal intratumoral fat attenuation
Logue LG et al. RadioGraphics 2003; 23:241–246
Almost pathognomonic for AML
Rare benign & malignant tumors considered
• Renal cell carcinoma
• Lipoma & liposarcoma
• Myolipoma
• Oncocytoma
• Wilms tumor
20. Angiomyolipomas (AMLs)
Rumack CM et al. Diagnostic Ultrasound. Elsevier-Mosby, St. Louis, USA, 3rd edition, 2005.
Large exophytic AML
Large exophytic AML
Central hemorrhage
Exophytic AML
Perirenal hematoma
21. Atraumatic renal & perirenal hemorrhage
• Malignant renal tumors Most common cause
• Benign renal tumors AMLs
• Vasculitis
• Aneurysm
• Systemic anticoagulation
• Infection
• Nephritis
Logue LG et al. RadioGraphics 2003; 23:241–246
25. Renal cysts seen in cortex & medulla
Appear at an earlier age than cysts seen in APKD
Tuberous sclerosis
Multiple renal cysts
Weber TM. Ultrasound Clin 2006 ; 1 : 15 – 24.
Not primary diagnostic feature
27. Malignant renal tumors
Renal cell carcinoma
Tumors of renal collecting system
28. Renal cell carcinoma
Most common primary malignancy of kidney
• 2% of all malignancies
• Increase incidence of RCC
• Improved survival rates
• Improved imaging technique & early diagnosis
• Classified histologically into five main types
• Mainly sporadic in occurrence, 4% familial in nature
Paspulati RM et al. Ultrasound Clin 2006 ; 1 : 25 – 41.
29. WHO classification of renal cell carcinoma – 2004
Type Incidence Grade Imaging features
Clear cell carcinoma 70 – 80% Low-grade tumor Poor enhancement
Paspulati RM et al. Ultrasound Clin 2006 ; 1 : 25 – 41.
Papillary type
Type 1
Type 2
10 – 15%
Low-grade tumor
Aggressive tumor
Poor enhancement
Intense enhancement
Chromophobe type 5% – –
Collecting duct type < 1% Aggressive tumor –
Medullary carcinoma < 1% Aggressive tumor
Common in sickle cell trait
–
Imaging cannot differentiate different histologic types of RCCs
31. Sonographic findings of RCC
• Hyperechoic mass < 3 cm – differentiated from AML
Anechoic rim (pseudocapsule)
Intratumoral cystic changes
• Isoechoic mass Differentiated from pseudo-tumors
Power Doppler & CEUS
• Hypoechoic mass
• Cystic mass (15%) Extensive necrosis of tumor
Multilocular Cystic RCC (MCRCC)
Paspulati RM et al. Ultrasound Clin 2006 ; 1 : 25 – 41.
32. Renal cell carcinoma
Paspulati RM et al. Ultrasound Clin 2006 ; 1 : 25 – 41.
Hypoechoic mass
in lower pole
Gray-scale US Color Doppler
Presence of vascularity
Pulsed Doppler
Arterial wave
33. RCC & arteriovenous fistula
Prando A et al. RadioGraphics 2006 ; 26 : 233 – 244.
Large A-V fistula within renal tumor
Fistula associated with intense venous flow to left renal vein
& periureteral veins causing ureteral notching
34. Intrarenal & venous propagation of RCC
Intrarenal propagation of lower-pole RCC to upper pole
Renal vein thrombus, IVC invasion,
& extensive collateral venous circulation
Prando A et al. RadioGraphics 2006 ; 26 : 233 – 244.
35. Intrarenal propagation of RCC
Exophytic hypoechoic solid mass (M)
Unusual diffuse hypoechogenicity of renal parenchyma (*)
Longitudinal US image of left kidney
Prasad SR et al. RadioGraphics 2006 ; 26 : 1795 – 1810.
36. Venous thrombosis in RCC
Rumack CM et al. Diagnostic Ultrasound. Elsevier-Mosby, St. Louis, USA, 3rd edition, 2005.
Enormous thrombus distending LRV
as it crosses midline anterior to aorta
Transverse sonogram
Large thrombus of IVC that
terminates caudal to level of HV
Sagittal sonogram of IVC
37. ADPKD & solid mass
Weber TM. Ultrasound Clin 2006 ; 1 : 15 – 24.
Solid renal masses in right kidney
Papillary renal cell carcinoma following nephrectomy
No increased risk for RCC in ADPKD except risk related to dialysis
38. Acquired cystic kidney disease with dialysis
ACKDD
Shrunken end-stage kidneys
Frequency increases with duration of dialysis
Complications: infection, hemorrhage, stone, erythocytosis, neoplasm
Screen native kidneys even after RT
Bates J A. Abdominal Ultrasound: How, Why and When.
Churchill Livingstone, Edinburg, UK, 2nd edition, 2004
39. Collecting duct carcinoma
< 1% of RCCs – Aggressive neoplasm
Prasad SR et al. RadioGraphics 2006 ; 26 : 1795 – 1810.
Solid hypovascular medullary neoplasm
Power Doppler sonogram
40. Cystic growth patterns of renal cell carcinoma
Yamashita Y et al. Acta Radiologica 1994 ; 35 : 19 – 24.
Rumack CM et al. Diagnostic Ultrasound. Elsevier-Mosby, St. Louis, USA, 3rd edition, 2005.
Multilocular
Unilocular
Cystic necrosis
Origin in wall of
simple cyst
41. Multilocular Cystic RCC (MCRCC)
3% of all RCCs
Kim JC et al. Korean J Radiol 2000 ; 1 : 104 – 109.
Multiloculated cystic mass
Enhanced thin septa without nodules
Some enhanced solid portions
CECT
Multilocular cystic mas
Multiple echogenic thin septa
Echogenic debris (blood clots)
Longitudinal US of right kidney
42. Cystic renal cell carcinoma
Complex cystic mass
4 thick internal septa
US of right kidney CECT
Enhancing soft-tissue
components within cyst
US 4 years later
Cystic mass with several
solid nodular components
Bosniak category III Bosniak category IV
Adilson P et al. RadioGraphics 2006 ; 26 : 233 – 244.
43. Bosniak classification of renal cysts
Category CT features Significance
Class I Water density homogenous
Noncalcified, smooth margin
No enhancing component
Benign
Chapple CR et al. Practical urology: Essential principles & practice.
Springer-Verlag, London , 2011.
Class II Thin septae (<1 mm)
Thin calcification (<1 mm)
Hemorrhagic cyst
Benign
Class IIF Likely benign
Follow-up imaging indicated
Class III Thick septa
Thick calcification
Thick wall
Multilocular +/− enhancement
≈ 50% malignant
Class IV Criteria of category III
Enhancing solid mass of wall or septa
Definitely malignant
44. Systematic screening for RCC by US
• 2-year screening program for general population (≥ 40 years)
• 2 urology departments at Mainz & Wuppertal university hospitals
• GP, internists & urologists experienced in renal US
• Equivocal or positive renal mass: referral to urology departments
• 9959 volunteers in first year, 79% returned in second year
• 13 subjects have renal mass (0.1%), 9 were RCC
• PPV of positive finding 50% & for equivocal finding 2%
Filipas D et al. BJU Int 2003 ; 91 : 595 – 9.
Screening program accepted by physicians & eligible population
Effective method if equivocal findings reassessed by reference
US before using further imaging studies (CT or MRI)
45. Sporadic & hereditary renal cancers
Choyke PL et al. Radiology 2003 ; 226 : 33 – 46.
Sporadic renal cancer
96%
Hereditary renal cancer
4%
Single Multiple & bilateral
Advanced age Younger age
More common in men Equal frequency in both sexes
Detected at larger size Detected at smaller size (screening)
47. von Hippel-Lindau disease
Rare disease (prevalence 1/ 35.000 – 40.000)
• Autosomal dominant disease with high penetrance
• Development of variety of benign & malignant tumors
• Broad clinical manifestations: 40 lesions in 14 organs
• Diagnostic criteria
More than one CNS hemangioblastoma
One CNS hemangioblastoma & visceral manifestations
Any manifestation & familial history of VHL disease
52. Leung RS et al.. RadioGraphics 2008 ; 28 : 65 – 79.
Multiple lesions of mixed echotexture
Multiple RCCs
von Hippel-Lindau disease (VHL)
Renal cell carcinoma (25 – 45%)
Sagittal US of left kidney CECT scan
Simple cysts
Solid enhancing lesions
Right nephrectomy (RCCs)
CBD stent (pancreatic cysts)
53. Screening protocol for VHL disease
Body System Regimen Follow-up
Renal Annual abdominal US from 10 y CT or MR
Depending on US findings
CNS MRI of brain & spine at 20 y
Annual neurologic exam if symptoms
Repeat imaging if suspicion
Adrenal Annual 24-h urinary VMA from 10 y
Annual blood pressure measurement
Imaging if VMA abnormal
Ophthalmic Annual ophthalmoscopy from 5 y
With or without fluorescein
–
Auditory Questionnaire
Audiogram if questionnaire positive
MRI If audiogram abnormal
Leung RS et al.. RadioGraphics 2008 ; 28 : 65 – 79.
54. Birt-Hogg-Dubé syndrome
Fibrofolliculomas, pulmonary cysts, & renal tumors
Choyke PL et al. Radiology 2003 ; 226 : 33 – 46.
Transverse chest CT scan
Several small pulmonary cysts
Asymptomatic 38-year-old woman
Screening because of family history of this syndrome
Transverse abdominal CT scan
Multiple solid renal cancers
Chromophobe carcinomas at surgery
55. Clinical criteria for diagnosis of HNPCC*
Amsterdam criteria II
• At least 3 relatives with HNPCC-associated cancer:
CRC, endometrium, small bowel, ureter, or renal pelvis
• One should be a first-degree relative of the other 2
• At least 1 should be diagnosed before age 50
• At least 2 successive generations should be affected
• Familial adenomatous polyposis should be excluded
• Tumors should be verified by pathological examination
* HNPCC: Hereditary Non-Polyposis Colon Cancer
Vasen HFA et al. Gastroenterology 1999 ; 116 : 1453 – 8.
56. Screening for hereditary renal cancer
No established guidelines
Choyke PL et al. Radiology 2003 ; 226 : 33 – 46.
Number of generalizations can be made
CT scan is the best single choice for screening
MRI if patients cannot undergo CECT (RF, allergy)
US not recommended (insensitive for small renal masses)
Mild phenotype Imaging every 2 – 3 years
Aggressive phenotype Imaging every 3 – 6 months
Intervals vary Longer interval for small lesions
58. Transitional cell carcinoma
Mass in renal pelvis causing slight hydronephrosis
in keeping with transitional cell carcinoma
Chapple CR et al. Practical urology: essential principles and practice.
Springer-Verlag, London , 2011.
59. Transitional cell carcinoma
Tissue harmonic imaging (THI)
Schmidt T et al. AJR 2003 ; 180 : 1639 – 1647.
Fundamental B-mode sonogram
Tumor of upper pole of kidney
Slightly hypoechoic to renal sinus
Border of process not well defined
Phase-inversion THI
Fewer scattering artifacts
Tumor better delineated
Internal structure of process visible
60. Better lateral & axial resolution
Enhanced signal-to-noise ratio
Reduced artifacts
Theoretic advantages of THI
Less degradation of sonographic images
61. Causes of upper tract filling defects
• Calculus
• Thrombus
• Tumor
• Sloughed papilla
• Fungus ball
• Pyelo-ureteritis cystica
Chapple CR et al. Practical urology: essential principles and practice.
Springer-Verlag, London , 2011.
62. Pyeloureteritis cystica
Rare abnormality (200 published cases)
• Older individuals, males = females, bilateral in 1/3
• Cause: irritating agent on epithelium especially infection
• Epithelial bodies below mucosa: cell nests of von Brunn
• Not appear to be premalignant lesion
• Symptoms: accidental, lumbar pain, UTI, hematuria
• IVP or retrograde urography is gold standard for dg
Multiple small (2–3mm) smooth filling defects
• No specific treatment
Salpigidis G et al. Hipokratia 2010, 14, 4 : 284 – 285.
63. Pyeloureteritis cystica
Chapple CR et al. Practical urology: essential principles and practice.
Springer-Verlag, London , 2011.
Duplex collecting system
Multiple rounded filling defects within left renal pelvis & ureters
64. Squamous cell carcinoma
Enlarged kidney
Chunky calcification with AS
Longitudinal US of left kidney CFD of left kidney
Increased vascularity in the mass
Large areas of necrosis
Paspulati RM et al. Ultrasound Clin 2006 ; 1 : 25 – 41.
Difficult to differentiate from XGPN by imaging
68. Schmidt T et al. AJR 2003 ; 180 : 1639 – 1647.
Metastatis of small cell bronchial carcinoma
Tissue harmonic imaging (THI)
Fundamental B-mode sonogram
Suspicious hypoechoic lesion
adjacent to right kidney
Phase-inversion THI
Clear solid exophytic mass
Hypoechoic rim (arrow)
Features of kidney clearly delineated
70. Renal lymphoma
Solitary lesion
Multiple lesions
Diffuse infiltration of one or both kidneys
Renal sinus involvement
Preferential involvement of perinephric space
Direct extension from retroperitoneal adenopathy
Wide variety of manifestations
Sheth S et al. RadioGraphics 2006 ; 26 : 1151 – 1168.
Unless renal lesion manifests in setting of widespread
lymphoma, percutaneous biopsy is indicated
71. Renal lymphoma
Solitary lesion (10 – 25% of patients)
Sheth S et al. RadioGraphics 2006 ; 26 : 1151 – 1168.
CECT scan
Low-attenuation mass in left kidney
thick walls lesion
Stranding in perinephric space
Transverse US of left kidney
Complex partially cystic mass
Thick wall & multiple septa
Minimal through transmission
72. Renal lymphoma
Multiple lesions (Most common, 50 – 60%)
Hypoechoic parenchymal masses
Normal shape of kidney
Transverse US of right kidney
Sheth S et al. RadioGraphics 2006 ; 26 : 1151 – 1168.
CECT scan
Bilateral renal masses
Lower attenuation than cortex
Paraaortic retroperitoneal adenopathy
73. Renal lymphoma
Paspulati RM et al. Ultrasound Clin 2006 ; 1 : 25 – 41.
Diffuse infiltration of one or both kidneys
Longitudinal gray-scale US of left kidney
Nephromegaly without distortion of the normal shape
More common in Burkitt lymphoma (disseminated or limited)
14.8 cm
74. Renal lymphoma
Renal sinus involvement – Uncommon
Poorly defined infiltrating
mass in renal pelvis
Sagittal US of left kidney Color Doppler US
Well vascularized kidney
Hypovascular mass
Sheth S et al. RadioGraphics 2006 ; 26 : 1151 – 1168.
75. Renal lymphoma
Preferential involvement of perinephric space (10% )
Differential diagnosis
Sarcoma from renal capsule
Metastases to perinephric space
Perinephric hematoma
Retroperitoneal fibrosis
Amyloidosis
Extramedullary hematopoiesis
Surrounding hypoechoic
perirenal mass
Rumack CM et al. Diagnostic Ultrasound. Elsevier-Mosby, St. Louis, USA, 3rd edition, 2005.
76. Renal lymphoma
Paspulati RM et al. Ultrasound Clin 2006 ; 1 : 25 – 41.
Direct extension from retroperitoneal adenopathy
Large hypoechoic mass
displacing & infiltrating left kidney
Mild hydronephrosis
Sagittal US of left kidney Transverse color Doppler
Mass encasing left renal artery
& vein
78. Leukemic involvement of kidney (rare)
• Focal renal mass (chloromas)
Acute myelogenous leukemia: seen in 10% of patients
Acute lymphocytic leukemia: less common
Focal hypovascular soft-tissue masses in one or both kidneys
• Diffusely infiltrating renal mass
• Perirenal mass
Perinephric extension of renal lesion
Isolated leukemic involvement
Surabhi VR et al. RadioGraphics 2008 ; 28 : 1005 – 1017.
Nonspecific imaging findings
Biopsy required to obtain definitive diagnosis
79. Leukemic involvement of kidney
Pickhardt PJ et all. Radiographics 2000 ; 20 : 215 – 243.
Leukemia in a 3-year-old boy with hypertension
Longituinal sonogram of right kidney
Enlarged heterogenous kidney
Loss of normal corticomedullary differentiation
81. Role of percutaneous biopsy in renal masses
Silverman SG et al. Radiology 2006 ; 240 : 6 – 22.
Established indications (sufficient data)
Emerging indications (more studies needed)
• Renal mass & known extrarenal primary malignancy
• Renal mass & findings suggesting unresectable renal cancer
• Renal mass & surgical comorbidities
• Renal mass that may be caused by infection
• Small, hyperattenuating, homogeneously enhancing renal mass
• Renal mass for which percutaneous ablation is considered
• Indeterminate cystic renal mass
82. Complications of renal biopsy for mass
• Bleeding Most frequent complication
Usually subclinical (90% by CT)
Major bleeding (transfusion) uncommon
PA & A-V fistula: months after biopsy
• Pneumothorax Uncommon
• Seeding along needle track: extremely rare (0.01%)
Silverman SG et al. Radiology 2006 ; 240 : 6 – 22.
Easily differentiated from renal mass:1- similar echotexture to adjacent renal parenchyma on gray-scale ultrasound.2- CFD and PD will demonstrate similar perfusion to that of adjacent renal parenchyma.
Another common renal variant that can be mistaken for renal scarring, a consequence of chronic infective process of the kidneys. Persistent fetal lobulation can be differentiated from scarred kidneys by the location of the renal surface indentations, which do not overlie the medullary pyramids as in true renal scarring, but overlie the space between the pyramids.The underlying medulla and the cortex are normal
Another common renal variant that can be mistaken for renal scarring, a consequence of chronic infective process of the kidneys. Persistent fetal lobulation can be differentiated from scarred kidneys by the location of the renal surface indentations, which do not overlie the medullary pyramids as in true renal scarring, but overlie the space between the pyramids.The underlying medulla and the cortex are normal
Prominent cortical tissue that is present between the pyramids and projects into the renal sinus. Prominent columns of Bertin are usually seen in the middle third of the kidney and are more common on the left side.
During normal development, there is partial fusion of two parenchymal masses called renunculi. Parenchymaljunctional defects occur at site of fusion & must not be confused with pathologic processes such as renal scars & angiomyolipoma. Junctionalparenchymal defect is most typically located anteriorly and superiorly and can be traced medially & inferiorly into renal sinus. Usually, it is oriented more horizontally than vertically; therefore, it is best appreciated on sagittal scans.It is seen more often on the right; however, when a good acoustic window is present (splenomegaly), it can also be seen on the left.
Presence of estrogen and progesterone receptors in angiolipomas has been reported, & such AMLs are more common in women & in TS.
Small RCCs can be hyperechoic and indistinguishable from an AML on sonography. Hypoechoic rim and intratumoral cystic changes are seen only in RCC, whereas acoustic shadowing is observed with AML.Rarely, RCCs can demonstrate fat attenuation caused by entrapment of the perinal or renal sinus fat, lipid necrosis, or osseous metaplasia. The characteristic intratumoral fat cannot be detected in 4.5% of AMLs. This finding has been attributed to minimal fat content or immature fat. These AMLs with low fat content demonstrate homogeneous and prolonged enhancement on a contrast enhanced scan, which distinguishes them from an RCC.
perirenal fat entrapment, lipid necrosis, or osseous metaplasia, all of which may occur in renal cell carcinoma
If TS is a consideration, the diagnosis can usually be confirmed on CNS imaging with subependymalhamartomasor giant cell astrocytomas.Multiple renal AMLs are a primary diagnostic feature of TS.Renal cysts are not the primary diagnostic feature of TS.
Tuberous sclerosis (Bourneville disease) is a phacomatosis, classically described as the triad of adenoma sebaceum, seizures, and mental retardation. The inheritance is autosomal dominant.
If TS is a consideration, the diagnosis can usually be confirmed on CNS imaging with subependymalhamartomas or giant cell astrocytomas. Presence of subependymal nodules and giant cell astrocytoma are sine qua non of TS.
Clear cell carcinoma: Arise from the proximal tubular epitheliumPapillary carcinoma Arise from the proximal tubular epitheliumChromophobe carcinomas Arise from the distal tubular epitheliumCollecting duct carcinomas Arise from collecting duct epithelium, most aggressive of all RCCs. Medullary carcinoma Subtype of collecting duct carcinoma that is more common in patients who have sickle cell trait.
US is less sensitive than CT & MRI in detecting small renal lesions, especially those that do not deform contour of the kidney.US is also less accurate than CT and MRI in staging of RCC.Despite these limitations, US is still the initial imaging modality for screening and characterization of renal mass lesions.
US is useful in detecting the venous invasion and for demonstrating the cranial extent of the inferior vena cava (IVC). McGahan and colleagues have reported a 100% sensitivity in the detection of renal vein involvement as compared with 89% sensitivity for IVC involvement by CFD sonography. Hence, US may be used as a complementary imaging modality when CT findings are equivocal in the assessment of venous extension of the tumor. The tumor thrombus is seen as an echogenicintraluminal mass causing distension of the vein.
No increased risk for RCC in patients who have ADPKD, except for: 1- increased risk related to dialysis2- generally increased risk for RCC in men
Multilocular cystic RCC (MCRCC) is an uncommon subtype of RCC and constitutes about 3% of all RCCs.MCRCCs have a benign clinical course and may benefit from nephron-sparing surgery.Crosssectional imaging with US and CT of MCRCC will demonstrate well-defined, multilocular cystic mass with thin septations. Dystrophic calcification and mural nodules are less common and MCRCC should be included in the differential diagnosis of all multilocular cystic renal mass lesions in adults. Small MCRCCs of less than 3 cm are hyperechoic on US and can mimic solid mass lesions, but show minimal enhancement on contrast-enhanced CT or MRI.Radiologic features: Well-defined multilocular cystic mass filled with serous, proteinaceous or hemorrhagic fluid, with no expansile solid nodules in thethin septa, but possibly with small, slightly enhanced solid areas constituting less than 10% of the entire lesion.
Birt-Hogg-Dubé syndromeCutaneous hair follicle tumors (fibrofolliculomas), pulmonary cysts, and renal tumors. Strong association with lung cysts and spontaneous pneumothorax has been established. The prevalence of this disorder is still unknown.Familial Renal OncocytomaThe diagnosis is based on the identification of multiple oncocytomas inherited in an autosomal dominant pattern. At imaging, the lesions are indistinguishable from malignant renal cancers and, thus must be treated as if they were renal cancers. When oncocytomas are extensive and confluent, the term renal oncocytomatosis can be applied.Because renal function is often compromised, these patients are often imaged with MR with gadolinium enhancement.Although metastases have not been seen in this small group of patients, the possibility of malignant transformation exists.Lifelong monitoring with imaging studies is recommended.
The risk factors include exposure to chemicals in petroleum, rubber, and dye industries; analgesic abuse; and chronic inflammations. Three morphologic forms of TCC are described:Focal intraluminal mass, mural thickening with narrowing of lumen, and infiltrating mass in the renal sinus. Excretory urogramhas been the primary imaging modality for the diagnosis of TCC and is being replaced by CT or MR urogram. These imaging modalities have the advantage of evaluating the entire urinary tract, which is crucial in the assessment of TCC.Sonography demonstrates a poorly defined hypo or hyperechoic mass in the renal sinus with or without pelvicaliectasis. The mass lesions are initially intraluminal and later invade the renal sinus fat and renal parenchyma.
Chunky: وافر مكتنزChronic irritation of the uroepithelium is the etiologic factor, which leads to squamous or columnar metaplasia of transitional epithelium. Renal calculi with longstanding hydronephrosis and inflammation are important predisposing factors for squamous cell carcinoma. Squamous cell carcinomas are more aggressive than TCC and the tumor manifests as an infiltrating mass involving the collectingsystem, renal sinus fat, and renal parenchyma.It is often difficult to differentiate squamous cell carcinoma of the renal pelvis from xanthogranulomatouspyelonephritis by imaging.
Renal lymphoma is commonly secondary to hematogeneous dissemination or contiguous extension from a retroperitoneal nodal disease.Renal lymphoma usually occurs in the setting of widespread non-Hodgkin lymphoma. In more than one-half of cases, renal or perirenal spread is detected at initial presentation. Involvement by Hodgkin disease is much less common, being seen in less than 1% of patients at presentation .Primary lymphoma is rare as there is no lymphoid tissue in the kidney.
CECT remains the modality of choice for the detection, diagnosis, staging, and monitoring of renal lymphoma. MRI is particularly useful in patients in whom intravenous administration of iodinated contrast material is contraindicated. Ultrasonography, although very valuable for diagnosing lymphoma in the testis or epididymis, is less sensitive than CT and MR imaging for detecting renal lymphoma. However, US may be the first test requested in patients who present with renal insufficiency or flank pain. US is also helpful in patients who are unable to receive intravenous iodinated contrast material.
stranding: حبل جديلة
Lymphomatous deposits enhance less than the normal renal tissue and appear as relatively homogeneous masses with lower attenuation than that of the surrounding cortex.Presence of retroperitoneal adenopathyis an additional clue to the diagnosis.
The differential diagnosis includessarcoma arising from the renal capsulemetastases to perinephric spaceperinephric hematomaRetroperitoneal fibrosisAmyloidosisExtramedullaryhematopoiesis.
Second most common pattern (25%–30% of cases).
Renal lymphoma is commonly secondary to hematogeneous dissemination or contiguous extension from a retroperitoneal nodal disease. Primary lymphoma is rare as there is no lymphoid tissue in the kidney.
Renal lymphoma is commonly secondary to hematogeneous dissemination or contiguous extension from a retroperitoneal nodal disease. Primary lymphoma is rare as there is no lymphoid tissue in the kidney.
The indications discussed herein may not apply to all patients, they should serve to guide clinicians, including radiologists, in determiningwhen and why to consider percutaneous biopsy in specific clinical settings. Renal mass and known extrarenal primary malignancyHelp differentiate a surgically resectable renal cell carcinoma from a metastasis. Pretreatment diagnosis is needed because virtually all metastases are treated medically; renal cell carcinomas are treated surgically.Renal mass & findings suggesting unresectable renal cancerBiopsy provides a tissue diagnosis that allows treatment to ensue, eliminating the need for surgery.If the renal mass biopsy findings revealed metastatic lung cancer, a subsequent biopsy of the lung mass would not be needed. However, if the biopsy of the renal mass revealed renal cell carcinoma, biopsy of the lung mass would still be required to differentiatemetastatic renal cell carcinoma from primary lung cancer.Renal mass & surgical comorbiditiesExamples of such comorbidities include heart and lung disease, the presence of a solitary kidney, and renal insufficiency. Renal mass that may be caused by infectionFocal bacterial pyelonephritis can appear masslike and mimic a renal tumor.Infectious cause should be considered to prevent unnecessary surgery in a patient with an infectious mass.Signs and symptoms of a urinary tract infection are usually present; however, on rare occasions, a urinary tract infection may be subtle and escape detection by the referring physician. Imaging findings of an infectious origin include ill-defined margins and perinephric stranding.If, after a careful history and laboratory evaluation, there is still the possibility of an infectious cause, percutaneous biopsy can be used to help confirm the diagnosis of cancer or identify an infectious cause. This scenario is uncommon, because most renal infections can be diagnosed clinically. Xanthogranulomatouspyelonephritis is an uncommon reaction to a bacterial infection that can manifest as a mass. Aspirates typically contain histiocytes and multinucleated giant cells. Small, hyperattenuating, homogeneously enhancing renal masssmall (< 3-cm), hyperattenuating (relative to renal parenchyma), homogeneously enhancing renal masses may represent benign tumors. Among these are angiomyolipomas with minimal or no fat.Most angiomyolipomas contain fat and can be diagnosed with unenhanced CT alone, approximately 5% of angiomyolipomas contain little or no fat. As a result, they can be indistinguishable from a small renal cell carcinoma. MR imaging can help to differentiate clear cell renal cell carcinoma from angiomyolipoma with minimal fat.Renal mass for which percutaneous ablation is consideredIndeterminate cystic renal massThe precise role of percutaneous biopsy in evaluation of the indeterminate (Bosniak type III) cystic renal mass is not certain.These cystic masses, often classified as Bosniak type III, typically contain more than a few septations, thickened septations, thickened walls, or non–borderforming calcification. Failure to retrieve malignant cells still leaves the radiologist, referring physician, and patient with the possibility that the lesion was improperly sampled or missed.Indeterminate cystic renal masses are often subjected to resection rather than biopsy.