solid renal masses imaging

DR DINU CHANDRAN NAIRDNB RESIDENTKG 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 IVPULTRA SONOGRAPHYCOMPUTED TOMOGRAPHYMRI.

Current role of IVP

o Detection of anomalies such as ureteral duplication,ureterocele.

o Complementary to retrograde pyelography andCT/MR for transitional cell carcinoma

o Alternative (suboptimal) to CT for evaluation ofall 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 IVPULTRA SONOGRAPHYCOMPUTED TOMOGRAPHYMRI.

ULTRA SONOGRAPHY

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

IMAGING MODALITIES.

X-RAY IVPULTRA SONOGRAPHY MRI.

COMPUTED TOMOGRAPHY

How to perform CT urography ?

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 delayo May add earlier phase (40 sec delay) if vascular anatomy is importanto 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 assessing Vascular Anatomy (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 cellcarcinoma. (a) Corticomedullary phase scan shows focal thinning (arrow) of the renal cortex, buta 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-suppressed T1-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-suppressed T1-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 replacerenal parenchyma without distorting its shape.

oExpansile masses distort the shape & these lesions lacksharp border of demarcation with normalParenchyma.

Axial CECT shows an enlarged right kidney with thestriated nephrogram pattern, characteristic; but notdiagnostic of acute pyelonephritis. The perirenal space isinflamed as well.

Axial CECT 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.

BENIGN MASSESRenal Cyts. PseudotumorsAMLRenal OncocytomaHemangiomaMALIGNANT MASSES

RENAL CELL CARCINOMARENAL MEDULLARY CARCINOMATRANSITIONAL CELL CARCINOMARENAL METASTASES AND LYMPHOMARENAL LEIOMYOSARCOMA.

LymphangiomaMultilocular Cystic NephromaLeiomyomaReninoma

PSEUDOTUMORSThis 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 intothe 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 (smallarrow) 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.

Fetal lobation

AngiomyolipomaMessenchymal Tumor.

Most common benign mesenchymal neoplasm.

Composed of variable proportions of blood vessels, smooth muscle, and adipose(faty) tissue .ASSOCIATIONAML present in 80% of TS 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

Imaging..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-phase T1-weighted gradient-refocused MR image shows bilateral multicentric renal masses that have increased signal intensity (arrows).B, Axial fat-saturated T2-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.

RENAL ONCOCYTOMA

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-enhanced T1-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

Hemangioma frequently arises from the renal pyramids or the pelvis.

Hemangiomas show variable echogenicity on sonography

hyperintensity on T2-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-saturated T2-weighted gradient-refocused echo MR image shows hyperintense left kidney mass in renal sinus (arrow).

Axial fat-saturated gadolinium-enhanced T1-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

LYMPHANGIOMA

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

CYSTIC NEPHROMA

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.

LEIOMYOMA

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

RENINOMA

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.

Conclusion

MALIGNANT RENALLESIONS

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.

Renal cell carcinoma:

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 high T2 signal.

Lesion show enhancement. Most RCC’S have a hypointense

pseudo capsule at the periphery of tumor.

MRI sensitive for IVC thrombosis.

Drawing of the anatomy of the retroperitoneal spaces at the level of the kidneys. The anterior pararenal space (APRS) is located between the parietal peritoneum (PP) and the anterior renal fascia (ARF) and contains the pancreas (Pan), the ascending colon (AC), and the descending colon (DC). The posterior pararenal space (PPRS) is located between the posterior renal fascia (PRF) and the transversalis fascia (TF). The perirenal space (PRS) is located between the anterior renal fascia and the posterior renal fascia.

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 featuresImaging 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.

Transitional cell carcinoma

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

(BEAN VS 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.

Faceless kidney in TCC

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 carcinomasRare Tumors.NCBI 2013 Jul 1; 5(3): e42.

Published online 2013 Sep 4. doi: 10.4081/rt.2013.e42

Case 1

Case 2

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

CASE 3

46 YEAR old male immunocompromised.

Case 4

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

Case 5

Case 6

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

Case 7

TAKE HOME MSG.

• Solid, expansile mass in adult is usuallyRenal cell carcinoma (85%), unless1)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 GUTReference Grainger 5th Edition

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