Ultrasound of the urinary tract - Renal cysts

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  • They are extremely common, the frequency increasing with age. They occasionally reach a considerable size of more than 10 cm, although they are usually 4 cm or less.Although cortical, they may be peripheral, extend from the surface of the kidney, or lie centrally, originating in the columns of Bertin. They often are multiple, particularly in the elderly, and when they are numerous, it is difficult to distinguish multiple cortical cysts fromautosomal dominant polycystic kidney disease (ADPKD).
  • Radiologic features that favor renal cell carcinomaPresence of blood in the tumor or in the perinephric space at CT or MR imagingRelatively large solid areas within the tumor mass, intravascular extension, or distant metastases. Findings suggestive of multilocular cystic nephromaAbsence of intratumoral or perinephric hemorrhageHerniation of a portion of the mass into the renal pelvis.
  • Also known as peripelvic cysts, parapelvic lymphatic cysts, parapelviclymphangiectasia, and parapelvic cyst.RSCs are likely lymphatic in origin or develop from embryologic rests.These cysts do not communicate with the collecting system.Most RSCs are asymptomatic, but they may become infected or bleed, and may cause hematuria, hypertension, or hydronephrosis
  • Multiple underlying factors have been proposed including:1- Abnormal development of the proximal ureteral smooth muscle2- Aberrant vessels, or bands crossing the upper ureter and renal pelvis3- Delayed recanalization of the fetal ureter4- Abnormal ureteral peristalsis.The ipsilateralureter is typically not dilated in children who have a UPJ obstruction, although ureteralvesical junction (UVJ) may occasionally coexist and result in a dilated ureter.
  • Parfrey PS et al. N Engl J Med 1990 ; 323 : 1085 – 90.US, because of high sensitivity and low cost, has become the primary method of diagnosing ADPKD and following the cysts.US screening for ADPKD typically begins between ages 10 & 15 years, (false negatives in 14% of patients younger than 30 years). Bear and colleagues developed criteria that are widely used to diagnose ADPKD. In adults who have a family history of ADPKD, the presence of at least three cysts in both kidneys, with at least one cyst in each kidney, is a positive finding.
  • Renal US & DNA analysis for ADPKD were performed in 319 patients who were at risk. PKD1: short arm of chromosome 16 – Account for 85 – 90 % of population with ADPKD.PKD2: Long arm of chromosome 4 – Account for 10 – 15% of population with ADPKD.In some other families, no linkage to either PKD1 or PKD2 has been reported.
  • 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
  • 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.
  • 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
  • Ultrasound of the urinary tract - Renal cysts

    1. 1. Ultrasound of the urinary tract Renal cysts Samir Haffar M.D. Department of Internal Medicine
    2. 2. Ultrasound of renal cysts • Common in population > 50 years (at least 50%) • Scanning technique is important Multiple positions: supine, LD, oblique, prone Scan with appropriate focal zone • Better demonstrated with THI: reduced background noise • Main goal: differentiate surgical from nonsurgical lesion Bosniak classification: based on CT scan Weber TM. Ultrasound Clin 2006 ; 1 : 15 – 24.
    3. 3. Bosniak classification Used worldwide in evaluating cystic renal masses • Originally described in 1986 & updated later • Not a pathologic but imaging & clinical management system • Developed on CT findings but applied to other modalities US Cannot alone accurately characterized cystic mass Except if renal mass is cystic (CT pseudoenhancement) MRI Often used when CECT contraindicated Higher Bosniak category than CT in some cases Israel GM & Bosniak M. Radiology 2005 ; 236 : 441 – 450.
    4. 4. 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
    5. 5. Simple cortical cyst Bosniak category I cyst Bosniak MA. Radiology 1986 ; 158 : 1 – 10. Paspulati RM et al. Ultrasound Clin 2006 ; 1 : 25 – 41. Three characteristics - Anechoic - Sharply defined smooth wall - Posterior acoustic enhancement If all these sonographic criteria are met Further evaluation or follow-up is not required
    6. 6. Tissue harmonic imaging (THI) Probable cyst on right kidney Evident internal echoes Gray-scale US THI “cleaned-up” image Removing internal echoes Simple renal cyst Application of THI McGahan J et al. Diagnostic ultrasound, Informa Healthcare, 2nd edition, 2008.
    7. 7. Better lateral & axial resolution Enhanced signal-to-noise ratio Reduced artifacts Theoretic advantages of THI Less degradation of sonographic images
    8. 8. Milk of calcium renal cyst Renal cyst with dependent echogenic material Mobile on real-time examination This kind of cyst is always benign Rumack CM et al. Diagnostic Ultrasound. Elsevier-Mosby, St. Louis, USA, 3rd edition, 2005.
    9. 9. Complex renal cyst Do not meet strict US criteria of simple renal cyst • 5-10% of all renal cysts are not simple cysts • 5-10 % of complex renal cysts prove to be tumors • Complex cysts: Wall thickening Septations & nodularity Calcification High attenuation (>20 HU at CT ) Signal not typical of water at MRI Enhancement • 2 main causes Complicated simple cyst, cystic RCC Hartman DS et al. RadioGraphics 2004 ; 24 : S101 – S115.
    10. 10. Paspulati RM et al. Ultrasound Clin 2006 ; 1 : 25 – 41. Minimally complicated renal cyst Bosniak category II cyst Renal cyst with thin septation Artifact from septation Frequently seen at real-time US
    11. 11. Cyst with mural nodule Complex cystic renal lesion Thick nodular septations Rumack CM et al. Diagnostic Ultrasound. Elsevier-Mosby, St. Louis, USA, 3rd edition, 2005. Complicated renal cyst Bosniak category III cyst
    12. 12. 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
    13. 13. CECT Enhancing soft-tissue components within cyst Cystic RCC Adilson P et al. RadioGraphics 2006 ; 26 : 233 – 244. Cystic mass with several solid nodular components US of right kidney Complicated renal cyst Bosniak category IV cyst
    14. 14. Multilocular cystic nephroma (MLCN) Benign nonhereditary cystic neoplasm • Multiple epithelially lined not communicating cysts Benign neoplasm usually, metastases have been reported • Bimodal presentation Males younger than 2 years Women during 5th – 8th decades • US:mass containing multiple cysts or internal septations Not possible to distinguish from multiloculated RCC Both are usually surgical lesions Weber TM. Ultrasound Clin 2006 ; 1 : 15 – 24.
    15. 15. Multilocular cystic nephroma (MLCN) Weber TM. Ultrasound Clin 2006 ; 1 : 15 – 24. Predominantly cystic mass Multiple internal septations Longitudinal US Better representation of lesion's internal architecture at US CECT scan
    16. 16. Multilocular cystic nephroma Multiloculated RCC Findings suggestive of MLCN Absence of intratumoral or perinephric bleeding at CT or MRI Herniation of portion of mass into renal pelvis Weber TM. Ultrasound Clin 2006 ; 1 : 15 – 24.
    17. 17. Renal sinus cyst Common (1.5 % in autopsy series) • Lymphatic in origin or develop from embryologic rests • Do not communicate with collecting system • Manifestations Most asymptomatic Infection, bleeding, HTN, hydronephrosis • Two patterns Parapelvic: single cyst in sinus & parenchyma Peripelvic: multiple confluent cysts in sinus The term renal sinus cyst recommended as generic description of any fluid-filled cyst found in renal sinus Rha SE et al. RadioGraphics 2004 ; 24 : S117 – S131.
    18. 18. Renal sinus cysts Do not communicate with collecting system Multiple renal sinus cysts Mimic hydronephrosis IVP, CECT, or MRI may be needed Rumack CM et al. Diagnostic Ultrasound. Elsevier-Mosby, St. Louis, USA, 3rd edition, 2005. Single renal sinus cyst Simple cyst located in renal sinus area
    19. 19. Ureteropelvic junction obstruction Bilateral in one fourth of children Severe UPJ obstruction Dilated calyces as large cysts Symmetrical in size Communicate by sonography Diminished renal parenchyma UPJ obstruction Dilatated intrarenal collecting system Right ureter not dilated Consistent with UPJ obstruction Sivit CJ. Ultrasound Clin 2006 ; 1 : 67 – 75.
    20. 20. Cyst puncture • Helpful in cases considered to be infected cyst or abscess • Rarely use for management decision about cystic masses Negative biopsy result does not rule out malignancy Evaluation portion of lesion may result in misdiagnosis • Complications: Tumor spread along needle track Rupture Bleeding Infection Hartman DS et al. RadioGraphics 2004; 24 : S101 – S115.
    21. 21. Multiple renal cysts • Polycystic kidney disease: ADPKD – ARPKD • von Hippel-Lindau disease (VHL) • Tuberous sclerosis (TS) • Acquired cystic kidney disease in dialysis (ACKDD) • Mulitcystic dysplastic kidney
    22. 22. Autosomal dominant polycystic kidney disease ADPKD Weber TM. Ultrasound Clin 2006 ; 1 : 15 – 24. 15.6 cm Cysts of variable size with bilaterally enlarged kidneys Compression of central sinus echo complex Nephrolithiasis (20 – 35 % of patients) Hepatic, pancreatic, ovarian, splenic, arachnoid, & other cysts
    23. 23. Differentiation simple cortical cysts from ADPKD • Multiple cysts At least 2 in each kidney after 30 years of age CT shows multiple smaller cysts not visible on US Distinction difficult in elderly: multiple cortical cysts • Family history of ADPKD • Coexistence of cysts in other organs • Gene markers for ADPKD McGahan J et al. Diagnostic ultrasound, Informa Healthcare, 2nd edition, 2008.
    24. 24. Screening of ADPKD Renal US & DNA analysis in 319 patients at risk Ravine D et all. Lancet 1994 ; 343 : 824 – 827. Nicolau C et al. Radiology 1999 ; 213 : 273 – 276. Person at risk & younger than 30 years Two cysts in one kidney or one cyst in each kidney Person at risk & aged 30 – 59 years Two cysts in each kidney Person at risk & aged 60 years or older Four cysts in each kidney Sen: 95% (ADPKD-1) – 65% (ADPKD-2) (Sen: 100%) (Sen: 100%)
    25. 25. Complicated ADPKD McGahan J et al. Diagnostic ultrasound, Informa Healthcare, 2nd edition, 2008. Weber TM. Ultrasound Clin 2006 ; 1 : 15 – 24. Echogenic cyst Patient pyrexial Aspiration reveals pus Infection Solid renal masses Papillary RCC Malignant tumorBleeding Echogenic cyst Aspiration reveals blood
    26. 26. Autosomal recessive polycystic kidney disease ARPKD • Varying degrees of renal failure & portal hypertension • Severe form After birth – renal disease predominates Neonatal US Kidneys enlarged bilaterally Oligohydramnios Potter’s facies Pulmonary complications • Later presentation Renal impairment & complications of CHF Ultrasound Kidneys maintain reniform shape Bilaterally enlarged & echogenic
    27. 27. ARPKD Right kidney 10 cm in length Bilaterally enlarged echogenic kidneys in a newborn Weber TM. Ultrasound Clin 2006 ; 1 : 15 – 24. Left kidney 9.8 cm in length
    28. 28. 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
    29. 29. Manifestations of VHL Disease 40 different lesions in 14 different organs Leung RS et al.. RadioGraphics 2008 ; 28 : 65 – 79. Manifestations Prevalence Pancreatic cysts Cerebellar hemangioblastoma Renal cysts Retinal hemangioblastoma Renal cell carcinoma Spinal cord hemangioblastoma Pheochromocytoma Neuroendocrine tumor of pancreas Serous cystadenoma of pancreas Medullary hemangioblastoma Papillary cystadenoma of epididymis 50 – 91% 44 – 72% 59 – 63% 45 – 59% 24 – 45% 13 – 59% 0 – 60% 5 – 17% 12 % 5 % 10 – 60%
    30. 30. Retinal hemangioblastoma Retinal angioma Leung RS et al.. RadioGraphics 2008 ; 28 : 65 – 79. Well defined orange-red mass Prominent feeding artery Prominent draining vein Ophthalmoscopic image Fluorescein angiogram Retinal angioma with its hyperfluorescence
    31. 31. von Hippel-Lindau disease (VHL) Renal cysts (60%) Simple renal cyst Leung RS et al.. RadioGraphics 2008 ; 28 : 65 – 79. Complex renal cyst Thick walls Septa Mural nodules Anechoic contents Sharply defined smooth wall Posterior acoustic shadowing
    32. 32. 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)
    33. 33. 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)
    34. 34. 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.
    35. 35. Tuberous sclerosis / Bourneville disease Autosomal dominant disease (prevalence: 1/10 000) • Hamartomatous growth CNS, eye, skin, heart, liver, kidney • Classic clinical triad Mental retardation Seizures Adenoma sebaceum (angiofibroma) • CNS manifestations Subependymal hamartomas (90%) Giant cell astrocytomas • Renal manifestations Angiomyolipomas (AMLs) (50%) Renal cysts Renal cell carcinomas (RCC)
    36. 36. Tuberous sclerosis (Bourneville disease) Features central to diagnosis Adenoma sebaceum Nontraumatic ungual periungual fibroma Hypomelanotic macules (three or more) Shagreen patch (connective tissue nevus) Multiple retinal nodular hamartomas Subependymal nodule Subependymal giant cell astrocytoma Cardiac rhabdomyoma (single or multiple) Renal angiomyolipoma Less specific features Multiple pits in dental enamel Hamartomatous rectal polyps Bone cysts Gingival fibroma Retinal achromic patch “Confetti”skin lesions Multiple renal cysts Logue LG et al. RadioGraphics 2003; 23:241–246
    37. 37. Tuberous sclerosis Multiple subependymal hamartomas T2 axial MR of brain T2 coronal MR of brain Weber TM. Ultrasound Clin 2006 ; 1 : 15 – 24. Primary diagnostic feature
    38. 38. 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
    39. 39. 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 Intratumoral fat on CT almost confirms diagnosis of AML
    40. 40. 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
    41. 41. Acquired cystic disease Bates J A. Abdominal Ultrasound: How, Why and When. Churchill Livingstone, Edinburg, UK, 2nd edition, 2004 Patients on long-term dialysis (shrunken end-stage kidneys) Frequency increases with duration of dialysis Potential for malignancy: screen native kidneys even after RT
    42. 42. Multicystic Dysplastic Kidney (MCDK) • Complete early ureteral obstruction (< 8th – 10th week) Incomplete ureteral obstruction later (10th – 36th week) • Contralateral renal anomalies: Most commonly UPJ obstruction in 33% of patients • US Large non communicating cysts Absence of identifiable cortical parenchyma Absence of central sinus structures • Calcify or not identifiable in few patients on follow-up
    43. 43. Multicystic dysplastic kidney (MCDK) Renal dysplasia Longitudinal view Transverse view Sivit CJ. Ultrasound Clin 2006 ; 1 : 67 – 75. Multiple parenchymal cysts of varying size Cysts do not communicate Absence of identifiable cortical parenchyma Absence of central sinus structures
    44. 44. Thank You

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