Focal Renal Lesions-MH

Focal Renal Lesions

Mindy M. Horrow, MD, FACR, FSRU

July, 2012

Outline

Cysts and cystic conditions

Complex cystic lesions: Bosniakclassification

Primary Malignant Tumors

Primary Benign Lesions

Metastatic disease

Other

Simple Cyst

CT: water density  10-15 HU,imperceptible wall, no enhancement

US: anechoic, imperceptible wall

MR: signal intensity typical of water,imperceptible wall

“notch”

Bosniak I lesion, a simple cyst

Small simple cyst

Pseudoenhancement of Renal Cysts

Pseudoenhancement (range, 10.3-28.3) may occurwith section collimation equal to or less than 50%of cyst diameter

Effect is maximal with small, 1.5 cm intrarenalcysts which are scanned during maximalparenchymal enhancement

No appreciable enhancement with exophytic cysts

Effect likely related to beam hardening

Maki, etal Radiology 1999;213:468-472

Bae, etal Radiology 2000;216:792-796

Birnbaum, etal Radiology 2002;225:83-90

Hereditary Renal Cystic Diseases inAdults: characterized by abnormal ciliaryfunction

Autosomal Dominant Polycystic Kidney Disease

–Abnormal function renal cilium with increased proliferationof tubular epithelium and increased fluid secretion

Medullary Cystic Kidney Disease

Von Hippel-Lindau Disease

Tuberous Sclerosis Complex

Non-Hereditary Renal CysticDiseases in Adults

Acquired cystic kidney disease

–Hyperplasia tubular epithelium with increased risk ofhemorrhage and renal cell carcinoma

Medullary sponge kidney

–Disruption embryonic interface getween ureteral bud andmetanephric blastema

Multicystic dysplastic kidney

–Abnormal differentiation in setting of obstruction duringembryogenesis

Localized renal cystic disease

–Pathogenesis unclear

Katabathina Radiographics 2012;30:1509-1523

APCKD2 different patients

Acquired Cystic Disease of Dialysistwo different patients

Cystic Renal Mass

Calcification

High Attenuation (>20 HU) on unenhanced CT

Signal intensity not typical of water

Septations

Multiple locules

Enhancement

Wall thickening

Nodularity

Bosniak Classification

I – simple benign cyst

II – benign cystic lesions that areminimally complicated

– few, thin septi,

–thin calcifications or short segment of minimallythick, but smooth calcification

–High density, non enhancing lesions < 3cm

Bosniak. Radiology 1986:158;1-10

Bosniak Classification

IIF (follow-up) likely benign but because ofcomplexity require follow up to prove benignity

–More septi

–Minimal thickening

–> 3cm, completely intrarenal high density lesion

–Recommend first follow up at 6 months and thenyearly for 5 years. Cyst can grow, looking forincrease in septations or wall thickening

Israel, Bosniak. AJR 2003:181;627

Bosniak Classification

III- very complex cystic lesion, contrastenhancing thickened septae, usuallyrequire removal but some of these lesionswill be benign

IV- partially cystic but frankly malignant,enhancing components other than wall

Issues with Bosniak Classification

Meticulous, dedicated CT is best modality forcystic mass categorization

Several parameters are qualitative (thickness,calcification)

Greatest inter-observer variability betweencategories II and III

Portion of mass that is most worrisome should beused in deciding category

Issues with applying Bosniakclassification

Small lesion with same type and number ofseptations as large lesion will appear more complex

Enhancement of hyperdense or heavily calcifiedlesions more difficult to assess, especially whensmall

Appreciate concept of pseudo enhancment thatoccurs when relatively small cyst (<2cm) issurrounded by enhancing parenchyma

Freire, Remer. AJR 2009;192:1367-1372

Ultrasound

Many cystic lesions discovered at US

Use highest frequency transducer whichcan penetrate kidney with color andpulsed Doppler for vascularity

Tissue harmonics can reduce noise

Useful in directing biopsies, ablations andpartial nephrectomy

We often find higher Bosniak score on UScompared to CT

CT Technique

Major method for characterizing cystic renallesions

Enhancement: dependent upon dose and rate ofcontrast administration

Triple phase approach probably optimal to look forenhancement and de-enhancement

–< 10 HU = benign cyst

–10 – 20 HU equivocal, but suspicious

–> 20 HU enhancement

MR Imaging

Major role in evaluation renal masses especially inpatients who cannot receive intravenous contrast

T1, T2, enhanced T1

Must standardize signal intensity for each exam.Contrast imaging within single series or imagesubtraction

Bosniak classification can be used, but with somecaveats: superior contrast resolution, inferiorspatial resolution

–Enhancement more obvious

–Septi and wall appear thicker

Bosniak Radiology 2012;262:781-785

Growing simple cyst: Bosniak I

Acute flank pain

Hemorrhage into cyst, no de-enhancement: Bosniak II

Hyperdense Cysts- Bosniak II Lesion

Hyperdense Cyst versus RCC

Non-contrast CT: homogeneous with >70HU, 99.9% hyperdense cyst

Non-constrast CT; hetergeneous with < 60HU likely renal cell carcinoma

Jonisch etal. Radiology 2007; 243:445

Bosniak 2

Thin septation, small calcification:Bosniak IIF lesion

Bosniak 2F

Negative for malignancy on aspiration

Presumed localized cystic renal disease

Non-Malignant Complex CysticLesions

Localized Cystic Renal Disease-

–uncommon, non-progressive disorder

–characterized by replacement of all or localized areas ofkidney by multiple variably sized cysts

–Aggregate of cysts appear like multiseptate mass, but nodistinct capsule or mural irregularities

Complex Benign Cystic Renal Lesions

–Complex features may be due to hemorrhage, infection,inflammation

–Bosniak II or IIF

History endstage renal disease

Right simple cysts, left Bosniak III: thick enhancing wall

Papillary renal cancer at surgery

Bosniak 3 Lesion

Multilocular Cystic Nephroma

Outcomes and AssociationsBosniak IIF and III lesions

Retrospective review

–IIF 62 patients

–III 131 patients

Resected lesions

–IIF 4/16 (25%) malignant

–III 58/107 (54%) malignant

Followed lesions

–IIF: 9/69 progressed and 4/8 operated were malignant

Associations

–History of primary renal malignancy, coexisting Bosniak IV lesionsand/or solid mass, multiple Bosniak III lesions were all associatedwith increased malignancy in Bosniak III lesions

Smith, Remer etal. Radiology 2012;262:152

“Bosniak 3”calcified wall limits evaluation

Bosniak 4 with enhancing component

Cystic clear cell carcinoma

Bosniak 4 lesion: measure most suspicious component

Cystic Renal Cell Carcinoma

Papillary type renal cell carcinoma

end stage kidney

Right Kidney Left Kidney

Bilateral Bosniak 4 lesions: numerousseptations, discreet solid components

Pre C Fat sat

Post C 1 min

Bilateral Bosniak 4 lesions

Bilateral Renal CellCarcinomas

Cystic Tumors

Cystic Clear Cell Carcinoma

–Cystic pattern in 4-15%

–Intrinsic cystic growth, cystic necrosis, origin in epithelium of simplecyst

Multilocular Cystic Renal Cell Carcinoma

–Rare, low grade tumor characterized by multiple septate cystsseparated from kidney by fibrous capsule

–Enhancing septae without any nodules

Multilocular Cystic Nephroma

Mixed Epithelial and Stromal Tumor

–Major female predominance (mean age 52), solid and cysticcomponents

Freire, Remer. AJR 2009;192:1367-1372

Renal Cell Carcinoma

Conventional clear cell -70% Chromophobe- 5%

Papillary (total 15% ) Type 1 Papillary Type 2

Histopathologic Subtypes of RCC

Ng etal. AJR2008;191:1220

Staging

Anatomic extent at diagnosis is single mostimportant factor in prognosis

5 year survival of 60 – 90% with organ confineddisease, 5 – 10% with distant metastases

Cell type also affects survival, spindle andanaplastic tumors with worse prognosis

2 Staging systems: Robson and TNM

Stage 1 Stage 2 Stage 3A

< 7cm > 7 cm Involving perinephric fat

From Ng. AJR 2008;191:1220

Stage 3A Stage 3B Stage 3C

Adrenal Gland Renal V/IVC SupradiaphragmaticIVC

From Ng. AJR 2008;191:1220

Renal Cell Carcinoma

Regional lymph nodes (N)

NX: Regional lymph nodes cannot be assessed

N0: No regional lymph node metastasis

N1: Metastasis in a single regional lymph node

N2: Metastasis in more than 1 regional lymph node

Laterality does not affect the N classification.

Distant metastasis (M)

MX: Distant metastasis cannot be assessed

M0: No distant metastasis

M1: Distant metastasis

AJCC Staging Groups

Stage I

T1, N0, M0

Stage II

T2, N0, M0

Stage III

T1, N1, M0

T2, N1, M0

T3a, N0, M0

T3a, N1, M0

T3b, N0, M0

T3b, N1, M0

T3c, N0, M0

T3c, N1, M0

Stage IV

T4, N0, M0

T4, N1, M0

Any T, N2, M0

Any T, any N, M1

Renal Cell Carcinoma

Associated genetic conditions: von-Hippel-Lindau,hereditary papillary renal cancer (autosomaldominant), tuberous sclerosis

More common in acquired cystic renal disease,long term dialysis (3-6x risk)

Suggested risk factors: cigarette smoking, obesity,diuretic use, petroleum products, chlorinatedsolvents, cadmium, lead, asbestos, ionizingradiation, high-protein diets, HTN, Renal TX, HIVinfection

Hereditary Renal Cell Carcinoma

Hallmarks:

–Multiple and bilateral

–Presents at younger age. Sporadic RCC usually in > 60 years

–Equal prevalence in women and men. Sporadic more common in men

–Family history may be positive, variable expressivity

Choyke, etal. Radiology 2003;226:33-46

Hereditary Renal Cell Carcinoma

Types

–Von-Hippel Lindau- RCC clear cell, type cysts,pheochromocytomas….

–Tuberous Sclerosis- AML, cysts, RCC papillary type

–Hereditary papillary renal cancer- papillary type 1

–Hereditary leiomyoma/RCC- papillary type 2 (cutaneous, uterineleiomyomas)

–Birt-Hogg Dube- RCC chromophobe type, also other types

–Hereditary renal oncocytoma

–Medullary carcinoma of kidney- associated with SS trait

–Lynch type 2- RCC clear cell type, associated cancer of colon,endometriaum, ovaries and stomach

Choyke, etal. Radiology 2003;226:33-46

Clear Cell Carcinoma

Without contrast with contrast

Is this a hyperdense cyst?

Bilateral Renal CellCarcinomas

Incidental renal cell carcinoma

Hematuria

Renal cell carcinomatumor thrombus into IVC

RCC with extension into renal vein,adenopathy, local spread, lung metastases

Routine CT for pain

Two years later

Missed renal cell carcinoma: difficulty of cortico-medullary phase

37 year old male with macroscopic hematuria

Renal cell carcinoma- chromophobe type

Chromophobe RCC

Third most common type of RCC in < 5%

Hyperechoic on ultrasound

Homogeneous enhancement on CT and MR often withspoke wheel pattern associated with oncocytoma

Similar pathologic features with oncocytoma

> 80% are stage 1 or 2 at presentation

Overall favorable prognosis but may develop hepaticmetastases

Prasad SR Radiographics 2006, 26:1795-1806

Von-Hippel Lindau

Rare autosomal dominant, multi-organ system disease(14) with benign and malignant tumors (40), highpenetrance with variable expression

Most common types and sites of involvement

Death usually 2° RCC or neuro compromise

Screening allows conservative TX to increase length andquality of life

–Hemangioblastomas: retinal, CNS

–Renal cysts (59-63%), tumors (24-45%)

–Pancreatic cysts, tumors

–Pheochromocytomas, endolymphatic sac tumors andepididymal cystadenomas

Leung Radiographics 2008;28:65

Post Operative Surveillance

Radical Nephrectomy

–T1 Yearly CXR

–T2 Abdominal CT @ 2 and 5 years, CXRs

–T3 Abdominal CT @ 2 and 5 years, CXRs

Partial Nephrectomy

–T1- None

–T2 Yearly CXR, Abdominal CT every 2 years

–T3 6-12 mos CXR, Abdominal CT every 6 months for3 years, then yearly

Lymphoma

6 months later

Elevated creatinine

Multifocal lymphoma

Patient with HIV

Lymphoma: lungs, liver, kidneys

Imaging Findings in Renal Lymphoma

Multiple masses- typically homogenous, slightlyhyperdense on unenhanced and hypodense afterenhancement

Solitary mass- very rare

Direct invasion from retroperitoneal disease- into renalhila, sinus, parenchyma. May invade and spreadalong ureter.

Diffuse infiltration of kidney without retroperitonealdisease, preserving reniform shape

Perirenal infiltration

Very hypoechoic but without posterior enhancement

Lymphoma in retroperitoneumgrowing into sinus of kidneys

Diffuse infiltrationboth kidneys

Other manifestations of renal lymphoma

Peri-renal disease

Historical Imaging of Lymphoma

Metastatic thyroid cancer to lung and kidneys

Pancreatic carcinoma metastatic to left kidney

History of lung cancer

Perirenal and adrenal metastases

6 months later

Renal Metastases

Most common primary tumors are lung, breast, GI

Frequency of metastases to kidneys at autopsy is 7% -13%

When renal metastases occur, disease is usually quiteadvanced

Metastases may be expansile or infiltrative

Most frequent pattern is multiple discrete bilaterallesions. Solitary lesions more common with coloncancer and perineprhic tumor extension is typical ofmelanoma.

Difficult to distinguish a single expansile mass from arenal cell carcinoma. Infiltrative lesions tend to bemetastatic

50 yo female

Tubular Spindle Cell Tumor (low grade collecting duct CA)

Described on pathology as large subcapsular mass, predominantlyencapsulated with small focus of invasion into renal parenchyma

Female predominance, favorable outcome

Transitional cell carcinoma

Left flank pain

Blunt trauma patient withhematuria

Transitional cell carcinoma

Transitional cell carcinoma with bone metastases

Urothelial tumor of renal pelvis

Predominantly papillary type

Accounts for over 90% renal pelvis tumors, small% are squamous cell

If bladder cancer, 2-4% develop upper tracttumors. If upper tract carcinoma, 20 – 48% risk ofbladder cancer in next 5 years

Bilateral in 2 – 10%

Peak incidence in 60 – 70 years

Biggest risk factor is cigarette smoking

Stone search, left flank pain

Spontaneous hemorrhage from angiomyolipoma

Multiple bilateralangiomyolipomas

Tuberous Sclerosis

24 year old

Slowly growing angiomyolipoma

Fat containing lesions on ultrasound measurelarger due to difference in speed of sound

Angiomyolipoma

Benign hamartomas composed of angioid, lipoidand myoid components: intratumoral fat is key toimaging diagnosis

Some contain large angioid component and arehypervascular with small aneurysms whichpredispose to hemorrhage

If < 4cm rarely symptomatic

If > 4cm may require embolization or surgery

Most common benign mesenchymal renal tumor

Small percentage without measureable fat on CT

Angiomyolipoma

Neoplasms of the perivascular epithelioid cells,which are also referred to as PEComas

–Classic triphasic tumors contain visible fat, > 90%

–Monotypic epithelioid are only soft tissue density andthus indistinguishable from RCC (rare, potentialmalignant)

Sporadic AMLs have 4 : 1 female predominance,accounting for 80% of all patients with AMLs

Tuberous sclerosis: 80% have AMLs, accounting for20% of patients with AMLs

Prasad et al. AJR. 2008; 190 (1): 158

Angiomyolipoma

Arise from subcapsular cortex with predominantexophytic growth

Difficult to distinguish from perinephric fat

Look for parenchymal notch to indicate origin oflesion

Liposarcomas are often at periphery of kidney andare exophytic, but typically have no identifiable fat

Liposarcomas (very rare) can arise from renalcapsule or within perinephric space

Renal Lipoma- presumed

Oncocytoma

Oncocytoma

Bilateral Oncocytomas

Oncocytomas

Benign tumors, no metastatic potential

Most common in middle to older agedmen

Homogeneous enhancement on CT

Pseudocapsule, central scar in biggerlesions

“Spoke wheel” arteriographic pattern

Prasad et al. AJR. 2008; 190 (1): 158

Oncocytomas

Typical solitary

May be bilateral in syndromes: multipleoncocytomas, Birt-Hogg-Dubé

Originates from or differentiates towardscollecting duct cells

May be associated with renal cellcarcinoma either as hybrids or collisiontumors

Prasad et al. AJR. 2008; 190 (1): 158

Multilocular CysticNephroma (presumed)

Ultrasound for right upper quadrantpain in a 43 year old woman

Multilocular Cystic Nephroma

Multilocular Cystic Nephroma

50% in males < 3 years

50% in females over 40

Expansile, multiloculated cystic mass

Herniation into collecting system is common

Enhancing septa on CT

Hypo or avascular on arteriography

Differential dx: cystic renal cell carcinoma,segmental multicystic dysplastic kidney, renalabscess

Leiomyoma of renal capsule

Leiomyoma

Rare, benign soft tissue neoplasms,occuring as incidental finding in adults

Most common in renal capsule, butoccasionally in cortex or pelvis

Usually well circumscribed, solid,homogeneously enhancing exophyticmass on CT, but can be quite variable

Prasad et al. AJR. 2008; 190 (1): 158

Other Benign Tumors

Lymphangioma

Hemangioma : associated with Sturge-Weber, Klippel Trenaunay, systemicangiomatosis

Papillary Adenoma

Juxtaglomerular Cell Neoplasm:“reninoma” a rare myoendocrine tumor

Prasad et al. AJR. 2008; 190 (1): 158

Renal Abscess

Right flank pain

Partial resolution after 2 weeks of antibiotics

Focal pyelonephritisbecoming an abscess

Renal Abscess

Clinical findings of infection

Hypoechoic with less throughtransmission than a cyst

Thick wall with rim enhancement on CT

Perinephric inflammation

Neovascularity in wall on angiogram

Focal Xanthogranulomatous Pyelonephritis

XGPN

Focal inflammatory mass may mimic malignancy,filled with lipid laden macrophages

Formed by tumefactive material, non-functional,but some enhancement may occur with contrast

History of chronic UTI

Solid or cystic mass, usually with renal calculus

Best treated with nephron sparing surgery

Sarcoidosis

Primary manifestation is functional, due toaltered calcium metabolism, may result inmedullary nephrocalcinosis and renalcalculi

Interstitial nephritis (striated nephrogram)and glomerulonephritis

Masses due to granulomatous lesions arevery rare

Radiographics 2004;24:87

Pseudotumors

Angiomyolipoma?

Pre-op: RCC

Partial nephrectomy withfat placed in defect

CT 2 weeks earlier, prior to ESWL

Left flank pain

Pseudotumor due toSubcapsular hematoma

McCrea, Katrina, acc spleen simul renal mass-3

McCrea, Katrina, acc spleen simul renal mass-1

McCrea, Katrina, acc spleen simul renal mass-2

Left Kidney

Pseudotumor dueto splenules

Sinclair, Shemeka, pancreatitis simul L renal mass-US-3

Sinclair, Shemeka, pancreatitis simul L renal mass-US-1

Sinclair, Shemeka, pancreatitis simul L renal mass-US-2

Sinclair, Shemeka, pancreatitis simul L renal mass-CT-5

Sinclair, Shemeka, pancreatitis simul L renal mass-CT-4

Pseudotumor due to swollentail of pancreas