SOLID RENAL MASSES imaging

DR DINU CHANDRAN NAIR
DNB RESIDENT
KG HOSPITAL
COIMBATORE
ADULT RENAL MASSES

EVALUATING RENAL MASSES
TECHNIQUE AND QUALITY
 The accurate diagnosis of a renal mass is
dependent on many factors, including the
clinical history, the nature of the imaging
findings, the experience of the radiologist,
and the quality of the examination

IMAGING MODALITIES.
X-RAY IVP
ULTRA SONOGRAPHY
COMPUTEDTOMOGRAPHY
MRI.

Current role of IVP
o Detection of anomalies such as ureteral
duplication,ureterocele.
o Complementary to retrograde pyelography and
CT/MR for transitional cell carcinoma
o Alternative (suboptimal) to CT for evaluation of
all etiologies of hematuria ± flank pain
i.e Calculi, tumor, infection, trauma, vascular

Nephrotomogram of IVU demonstrates loss of the normal lateral contour
of the left kidney and calyceal splaying

IMAGING MODALITIES.
X-RAY IVP
ULTRA SONOGRAPHY
COMPUTEDTOMOGRAPHY
MRI.
ULTRA SONOGRAPHY

USG
 Sensitivity of Usg is good but has poor Specivity for
diagnosis.

IMAGING MODALITIES.
X-RAY IVP
ULTRA SONOGRAPHY

MRI.
COMPUTEDTOMOGRAPHY

O 1000 cc water orally 15 to 20 min prior to CT (to
produce diuresis)
O Nonenhanced scans through kidneys (diaphragm to
Iliac crest)
O 100 to 125 ml nonionic contrast IV at 3 ml/sec
O After 3 min , roll patient 360 (to opacify all
segments of bladder and collecting system)
o Scan diaphragm to pubis with 80 – 100 sec delay
o May add earlier phase (40 sec delay) if vascular
anatomy is important
o Rarely add 10 min delay in event of high grade
ureteral obstruction.

Corticomedullary Phase: 25 – 70 sec
Importance: Mass enhances less than the cortex.
Best for assessingVascularAnatomy (both renal vein & arterial )
Nephrographic Phase: 80 – 180 sec
Most sensitive for detecting abnormal contrast enhancement.
Delayed Phases: 10 min
Collecting system involvement.

Arterial phase good for diagnosing column
of Bertin;
pyelographic phase essential for diagnosing transitional
cell cancer.

Transverse contrast-enhanced CT scans in a 54-year-old woman with a renal cell
carcinoma.
(a) Corticomedullary phase scan shows focal thinning (arrow) of the renal cortex,
but
a definite renal mass is not identified in this early phase of renal enhancement.
(b) Nephrographic phase scan shows a 1.5-cm intrarenal mass (arrow), which was
surgically proved to be renal cell carcinoma.

MR IMAGING
 All sequences are performed during an end-
expiratory breath hold, and, for those patients who
cannot hold their breath for a sufficient period of
time (approximately 20 seconds), 2 L/min oxygen is
given via a nasal cannula.
 By using cushions, the patients’ arms are elevated
anterior to the level of their kidneys to avoid a wrap
around artifact in the coronal acquisitions.

 In all patients referred for evaluation of a renal mass,
MR angiography, MR venography, and MR urography
are performed by using an oblique coronal
breathhold 3D fat-suppressedT1-weighted spoiled
gradient-echo sequence before and after contrast at
multiple time points.
 after administration of 19 mL of a gadolinium-based
contrast material.The 3D slab should be kept as thin
as possible, without excluding any of the structures
that need to be evaluated, to maximize through-
plane spatial resolution

 To evaluate the renal parenchyma and a renal mass, a separate
3D breath-hold fat-suppressed T1-weighted spoiled gradient-
echo sequence is performed in the transverse plane before and
after contrast material administration.
 The postcontrast acquisition is performed between MR
venography and MR urography.
 For the characterization of renal masses and to determine the
presence or absence of enhancement, its recommended an
imaging delay of 3–5 minutes.

Transverse fat-suppressedT1-weighted MR images in a 68-year-old man with a complex
renal mass.
(a) Unenhanced image shows a hemorrhagic mass (arrows) at the upper pole of the left
kidney.
(b) (b) Gadolinium-enhanced image shows enhancement of a thickened wall (arrows),
but it is difficult to determine if there is any internal enhancement within the mass
because of its heterogeneous signal intensity a. A small portion of enhancing renal
parenchyma (arrowhead) is present anterior to the mass.
(c) (c) Subtracted image (gadolinium-enhanced image minus unenhanced image)
shows nodular enhancement (large arrow) along the wall of the mass and internal
enhancement (small arrows), confirming the diagnosis of a renal cancer.
A papillary renal cell carcinoma was diagnosed at surgical pathologic evaluation.

Differentiating enhancing from non
enhancing renal masses
Most important criteria
 Renal mass enhancement is dependent on multiple
factors, including the amount and rate of the contrast
material injection, the imaging delay, and the nature of
the tissue within the mass.
 When there is a question of whether a mass enhances at
CT, Hounsfield unit measurements should be obtained and
compared on the unenhanced and contrast- enhanced
images.
 conventional (nonhelical) CT scanners, a difference of 15 -
20 HU is suggested as evidence of enhancement
(Reference DI series by Michael P Federal "Expert
Differential Diagnoses")

• Infiltrative refers to processes that replace
renal parenchyma without distorting its shape.
oExpansile masses distort the shape & these lesions lack
sharp border of demarcation with normal
Parenchyma.

AxialCECT shows an enlarged right kidney with the
striated nephrogram pattern, characteristic; but not
diagnostic of acute pyelonephritis.The perirenal space is
inflamed as well.

AxialCECT shows heterogeneous decreased enhancement of the
lower pole of the right kidney _ Simulating an infiltrative mass,
but proved to be due to acute renal infarction.

Differentiating surgical from non
surgical renal masses
 In most cases, it is possible to preoperatively differentiate
those renal masses that require surgery (renal cell
carcinoma, invasive transitional cell carcinoma, and
oncocytoma) from those that do not.
 Renal cell carcinoma and oncocytoma are indistinguishable
from each other at imaging.
 However, angiomyolipoma, lymphoma, metastatic disease,
renal anomalies, and other pseudotumors can all mimic renal
cell carcinoma.
 Before making a diagnosis of renal cell carcinoma, one
should be make sure that none of these possible mimickers
of renal cell carcinoma are potentially present.

Renal Cyts.
Pseudotumors
AML
Renal Oncocytoma
Hemangioma
RENAL CELL CARCINOMA
RENAL MEDULLARY CARCINOMA
TRANSITIONAL CELL CARCINOMA
RENAL METASTASES AND LYMPHOMA
RENAL LEIOMYOSARCOMA.
Lymphangioma
Multilocular Cystic Nephroma
Leiomyoma
Reninoma

This group includes congenital anomalies and
inflammatory masses.
A renal pseudo tumor represents normal renal
tissue that may mimic a renal neoplasm.
 Congenital pseudotumors are normal variants
which include prominent renal columns of Bertin,
renal dysmorphism, and dromedary humps.
 Acquired pseudotumors represent
hypertrophied normal renal parenchyma
assuming a tumorlike appearance adjacent to
parenchymal scarring.

It is advantage of the corticomedullary phase to demonstrate the
normal corticomedullary differentiation in the suspected “mass.”
Inflammatory masses, including focal pyelonephritis and renal
abscess, may also mimic the appearance of a renal neoplasm.
However, with the appropriate clinical history the correct diagnosis
usually becomes apparent.
The differentiation of a cystic renal neoplasm from a subacute or
chronic renal abscess can be difficult when the typical clinical
findings of infection are not present.
If a remote history of fever, leukocytosis, or urinary tract infection
is obtained, needle aspiration should be performed, and if pus is
recovered, percutaneous drainage can be instituted.
However, if blood or necrotic debris is recovered, surgical removal
is indicated

Axial CECT shows normal renal cortex, a column of Bertin protruding into
the renal sinus.This is a common anomaly and usually occurs at the junction
of the upper & middle thirds of the kidney.

Transverse contrast-enhanced CT scans in a 63-year-old man with a left renal
pseudotumor.
(a) Nephrographic phase scan shows a focal “mass” (large arrow) adjacent to a
scar (small
arrow) in the left kidney.The left kidney is smaller than the right kidney, and
the mass enhances identically to the renal parenchyma.
(b) Corticomedullary phase scan shows corticomedullary differentiation in the
renal “mass,” diagnostic of localized hypertrophy of normal renal parenchyma.

Messenchymal Tumor.
Most common benign mesenchymal neoplasm.
Composed of variable proportions of blood vessels, smooth
muscle, and adipose(faty) tissue .
ASSOCIATION
AML present in 80% ofTS patients
CNS: giant cell astrocytoma, subependymal/cortical tubers
Lymphangioleiomyoamtosis (a/w chylous effusion)
Cardiac rhabdomyoma
Adenoma sebaceum, shagreen patches

Renal AMLs consist of two distinct histologic
subtypes, classic and monotypic epithelioid.
 Epithelioid AMLs typically do not show
macroscopic fat and appear as soft-tissue
masses and are thus indistinguishable from
other solid renal masses.
 This rare subtype of AML is potentially
malignant and may exhibit aggressive
biology, including recurrence, metastasis, and
death

 Classic AML may occur either sporadically or in association
with tuberous sclerosis complex (TSC).
 Sporadic renal AMLs show a 4:1 female preponderance and are
more likely to be solitary and asymptomatic
 Large tumor size (> 4 cm) and diameter of the intralesional
aneurysms (> 5 mm) correlate directly with tumor-related
hemorrhage in AMLs
 On sonography, small AMLs appear uniformly hyperechoic
without a hypoechoic rim or intralesional cysts .
 Large AMLs appear as variegated masses with macroscopic
fat, hemorrhage, and hypervascular soft-tissue components

USG.
On sonography, small AMLs appear uniformly hyperechoic
without a hypoechoic rim or intralesional cysts
Large AMLs appear as variegated masses with macroscopic fat,
hemorrhage, and hypervascular soft-tissue components

CT and MRI
 The presence of macroscopic fat on CT or MRI is
characteristic of AMLs.
 Loss of signal intensity on frequency-selective fat-
suppressed MRI definitively identifies macroscopic
fat .
 However, a multitude of renal neoplasms, including
RCC, oncocytoma, lipoma, and liposarcoma, may
show either intratumoral fat or engulfed perirenal
fat
 Recent studies indicate that in contradistinction to
RCCs, AMLs with minimal fat show uniform,
prolonged contrast enhancement and a higher
signal intensity index on IN PHASE OUT PHASE,
chemical shift FLASH MRI.

43-year-old woman with
hematuria.Transvers
sonogram shows uniformly
echogenic mass (arrows)
in upper pole of left kidney (K)
that was proven to be
angiomyolipoma
58-year-old woman with
angiomyolipoma of kidney.
Sagittal contrast-enhanced CT
scan shows exophytic renal mass
(arrows) with foci of macroscopic
fat (arrowhead).

38-year-old woman with documented tuberous sclerosis complex and renal
angiomyolipomas.
A, Axial In-phaseT1-weighted gradient-refocused MR image shows bilateral
multicentric renal masses that have increased signal intensity (arrows).
B, Axial fat-saturatedT2-weighted gradient-refocused MR image shows
marked drop in signal intensity of masses (arrows)

It is important to realise that a proportion of
angiomyolipomas are fat-poor.This is especially
the case in the setting of tuberous sclerosis, where
up to a third do not demonstrate macroscopic fat
on CT.

Macroscopic fat in RCC(Rare) almost always occurs in the
presence of ossification/calcification, absence of
ossification/calcification on imaging is in favour of AML.

 Peak age of incidence 70 yrs
 Males > females
 Histologicaly contains Oncocytes.
 Oncocytomas typically appear as solitary, well-
demarcated, unencapsulated, fairly homogeneous renal
cortical tumors.
 Bilateral, multicentric oncocytomas are seen in hereditary
syndromes of renal oncocytosis and Birt-Hogg-Dubé
syndrome.

 A characteristic central stellate fibrotic scar (more often
seen with large tumors) is seen in up to 33% of tumors
 Hemorrhage may be found in up to 20% of cases.
 A spoke-wheel pattern of feeding arteries associated
with a homogeneous nephrogram is a characteristic
finding on catheter angiography .
 However, oncocytomas are indistinguishable from
renal cell carcinomas on the basis of imaging findings
alone.

64-year-old man with histologically proven oncocytoma. K = kidney.
Axial fat-saturated,T2-weighted gradient-refocused echo image shows
expansile, solid right renal mass(arrow) with hyperintense central scar (S).
B, Axial fat-saturated, gadolinium-enhancedT1-weighted 3D gradient-
refocused echo image shows right kidney mass (arrow) with hypointense
central scar (S)

 rare benign mesenchymal neoplasm that consists of
multiple endothelium-lined, blood-filled vascular spaces .
 It commonly affects young adults with no specific sex
predilection.
 Recurrent episodes of hematuria and renal colic are
typical presenting symptoms;
 may be associated with systemic syndromes such as
Sturge-Weber and Klippel-Trénaunay and with systemic
angiomatosis .
 Cavernous hemangiomas are more common than the
capillary variants

 Hemangioma frequently arises from the renal
pyramids or the pelvis.
 Hemangiomas show variable echogenicity on
sonography
 hyperintensity onT2-weighted MRI
 Contrast-enhanced CT and MRI of renal
hemangiomas may show early, intense
enhancement .
 Persistent contrast enhancement on delayed
images is fairly characteristic of renal
hemangiomas.

60-year-old man with hematuria and histologically proven hemangioma.
 Axial fat-saturatedT2-weighted gradient-refocused echo MR image shows
hyperintense left kidney mass in renal sinus (arrow).
Axial fat-saturated gadolinium-enhancedT1-weighted gradient-refocused echo
MR image shows contrast enhancement of left renal sinus mass (arrows).

 Rare benign cystic tumor
 Often arises from peri pelvic region or renal sinus.
 Renal lymphangioma may occur either as an isolated
finding or in association with perinephric or systemic
lymphangiomatosis.
 It may appear as a localized process or a diffusely cystic
lesion.
 typically appears as a well-demarcated, uni- or
multilocular cystic neoplasm that most commonly
arises from the renal sinus region or in the perinephric
space

47-year-old man with bilateral multiple renal sinuses and perinephric
lymphangiomatosis.
Unenhanced axial CT scan shows multicentric cystic masses in renal sinus
and perinephric spaces (arrows).

 Cystic nephroma is a benign cystic neoplasm that affects
predominantly middle-aged, perimenopausal women.
 Adult-onset cystic nephroma is histogenetically and
morphologically different from pediatric cystic nephroma
 Morphologically, cystic nephromas are composed of
encapsulated, noncommunicating cysts with thin septations.
 Septa show no enhancement. Calciftn of septa may be seen
 cystic nephromas are characterized by the absence of a solid
component or necrosis.
 The cystic mass may protrude into the renal pelvis and cause
hemorrhage or urinary obstruction
Central location, with renal sinus prolapse
(pathognomonic

14—50 year-old woman with cystic nephroma.
 Coronal contrast-enhanced CT scan shows lobulated, expansile,
cystic mass (M) in left kidney (arrow) that compresses calyces (C).

Renal leiomyomas are rare benign smooth muscle neoplasms that
mostly occur in adults as incidental findings .
 Renal capsule is the most common target site of leiomyomas.
rarely, leiomyomas originate from the renal pelvis or cortex.
Calcification is uncommon.
However, the CT findings of leiomyomas of the kidney may be
variable and may include cystic, complex cystic–solid, or purely solid
morphology .
Renal leiomyomas may show hypervascularity on catheter
angiography because they are predominantly supplied by capsular
vessels.

43-year-old woman .
Axial contrast-enhanced CT scan shows large, fairly homogeneous exophytic
mass(arrows) arising from left kidney (K).
Leiomyomas of the kidney commonly appear as well-circumscribed,
homogeneous, exophytic solid masses that show uniform enhancement on
contrast-enhanced CT .Larger tumors are heterogeneous because of hemorrhage
and cystic or myxoid degeneration.

 Juxtaglomerular cell (JGC) neoplasm is an extremely rare, benign
renal neoplasm of myoendocrine cell origin .
 The peak age of incidence is in the second and third decades and
a 2:1 female preponderance is seen.
 JGC neoplasm is clinically characterized by a triad of findings:
poorly controlled hypertension, hypokalemia, and high plasma
renin activity
 JGC neoplasm typically appears as a unilateral, well-
circumscribed, cortical tumor that usually measures less than 3
cm.
 Despite profuse vascularity, JGC neoplasms appear hypovascular
on contrastenhanced CT and MRI, possibly because of renin-
induced vasoconstriction.
 JGC neoplasms may show delayed contrast enhancement.
 Imaging findings of JGC neoplasms are nonspecific and
indistinguishable from other solid renal neoplasms

23-year-old woman with hypertension refractory to standard treatment.
Axial unenhanced CT scan shows large, expansile right renal mass (arrow)
that was histologically proven to be juxtaglomerular cell neoplasm
(reninoma). K = kidney, M = mass

 leiomyomas originate from the renalcapsule,
hemangiomas typically arise from the renal sinus.
 Approximately one third of large oncocytomas typically
show a central stellate scar.
 Cystic nephromas show septated cysts,
 macroscopic fat predominates in most
angiomyolipomas.

 Pathologically adenocarcinoma
 Common in adults & also in Males
 Associated with cigarrette smoking
 Symptoms: pain hematuria, wt loss and abdominal
distension.
 IMAGING: focal renal mass centered in renal cortex.
 Mass distorts the margins
 Calcifications 25%. Common in larger lesions than small
 Often renal vein invasion.Thrombus may extend into ivc.
 Thrombus may show arterial enhancement.

 Do not usually metastasize when less than 3 cms.
 Mets: to liver, lung bone and nodes.
 Liver mets often hypervascular.
 Mets to retro peritoneal space has poor prognosis
 MRI: typically mild hypointense to renal cortex on
T1 and mildly highT2 signal.
 Lesion show enhancement.
 Most RCC’S have a hypointense pseudo capsule at
the periphery of tumor.
 MRI sensitive for IVC thrombosis.

Drawingoftheanatomyoftheretroperitonealspacesatthelevelofthekidneys.The
anteriorpararenalspace(APRS)islocatedbetweentheparietalperitoneum(PP)andthe
anteriorrenalfascia(ARF)andcontainsthepancreas(Pan),theascendingcolon(AC),and
thedescendingcolon(DC).Theposteriorpararenalspace(PPRS)islocatedbetweenthe
posteriorrenalfascia(PRF)andthetransversalisfascia(TF).Theperirenalspace(PRS)is
locatedbetweentheanteriorrenalfasciaandtheposteriorrenalfascia.

Renal cell carcinoma (Robson staging system)
Stage I: confined within capsule of kidney
Stage II: invading perinephric fat but still contained within
Gerota’s fascia, includes ipsilateral adrenal involvement
Stage III:
III-a: invading renal vein or IVC
III-b: regional lymph-node involvement
III-c: both nodes and IVC/renal vein involvement
Stage IV: invading adjacent viscera (excluding ipsilateral adrenal)
or distant metastasis

RENAL MEDULLARY CARCINOMA
rare variant of renal cell cancer
Radiographic features
Imaging demonstrates a centrally located infiltrative
lesion invading the renal sinus with peripheral
caliectasis, reniform enlargement, and smaller
peripheral satellite nodules.
There is heterogeneous enhancement at CT, and US
shows heterogeneous echotexture.
D/d TCC

 Urothelial tumors are less common in upper
urinary tract.than RCC
 Second most renal neoplasm in adults
 Risk factors: nsaids, tobacco etc.
 Common in males
 Increased in horse shoe kidney
 Present with hematuria
 Initial detection done on IVP
 Ocasionally usg may detect a collecting system
lesion in calyces or renal pelvis.

 3 general ct imaging appearance:
 Smal hypodense lesion in collecting system
 Soft attenuation value HU<40 less than calculi and clot.
 Enhance 10-50 hu
 Enhancemnt less than surrounding renal parenchyma
 Stippled calcifications
 Necrosis in large lesion is uncommon
 Do not involve renal vein
 May present as infiltrative renal mass
 Mass originates from centre of kidney
 Renal contour usually not disrupted unlike RCC (BEANVS
BALL)

 Expansion of collecting system above the area.
 Tumor insitu and limited to sub mucosa have best
prognosis.
 Stage2: invasion beyond subepithelial tissue.
 Stage 3: muscularis, invasion of renal parenchyma,or
peri pelvic/periureteral fat.
 Stage4: nodal involvement., organs bone and lungs.

Renal lymphoma
NHL >> Hodgkin’s lymphoma
Patterns of involvement:
MC direct extension of retroperitoneal disease
Hematogenous extension (common)
Primary renal lymphoma (rare) .
Features:
Multiple hypoechoic(USG), hypodense(CT) masses
Diffuse involvement .
Adenopathy

Renal leiomyosarcomas may arise from the smooth
muscle fibers of renal pelvis, renal capsule or renal
vessels, last one is the most frequent.
RENAL LEIOMYOSARCOMA
Extremely rare tumor.
Symptoms an signs occurring at late stages of the
disease: abdominal pain, palpable mass, vomiting,
hematuria and weight loss.
 Neither ultrasonography, tomography or magnetic
resonance are able to differentiate between
leiomyosarcomas an renal cell carcinomas
RareTumors.NCBI 2013 Jul 1; 5(3): e42.
Published online 2013 Sep 4. doi: 10.4081/rt.2013.e42

Renal infarct
Case findings:
Global infarct of the right kidney with rim of enhancement in capsule (cortical
rim sign)
Etiology:
Thromboembolism
Septic emboli, atherosclerosis
Aneurysm of aorta or renal artery
Dissection of the aorta or renal artery
Vasculitis: PAN, SLE, drug-induced
Trauma, hypercoagulable state
Acute renal vein occlusion

46YEAR old male immunocompromised.

Case 4
32 year old female with h/O flank pain and hematuria following
blunt trauma abdomen.

Case 6
48 yr old male with hematuria,flank pain & fever for 5days.

• Solid, expansile mass in adult is usually
Renal cell carcinoma (85%), unless
1)Mass contains fat (probably angiomyolipoma)
2) Patient has fever, urosepsis (consider pyelonephritis &
renal abscess)
3)Patient is immunocompromised (consider lymphoma)
4) Patient has known other primary cancer(consider
metastases)
Reference DI series GUT
Reference Grainger 5th Edition

SOLID RENAL MASSES imaging

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