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Imaging of Renal Tumors

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Basics of imaging of Renal tumors

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Imaging of Renal Tumors

  1. 1. Dr. Yash Kumar Achantani OSR
  2. 2. 1. Plain abdominal radiography 2. Intravenous urography 3. Radionuclide imaging 4. Ultrasound 5. Computed tomography 6. Magnetic resonance imaging 7. Renal arteriography 8. Needle aspiration
  3. 3. The plain abdominal radiograph (KUB—kidneys, ureters, bladder) is rarely used to diagnose a renal mass. Loss of the psoas margin or displacement of retroperitoneal fat may suggest the presence of one, as may an opacity projected over the renal outline, or a loss of the renal outline. Central calcification within a renal mass is more suggestive of malignancy than peripheral calcification (87% versus 20–30%).
  4. 4. Intravenous urography (IVU) is a relatively insensitive method of detecting small renal masses, particularly if they occur centrally rather than peripherally; cross-sectional techniques are a more appropriate method of investigating a patient with a suspected renal mass.
  5. 5. Differentiation between a definite mass and an anatomical variant that simulates a mass (pseudotumour) can be made using radionuclide imaging; however, this is rarely useful in practice.
  6. 6. US is usually the first method of evaluating a patient for a renal mass and is the most appropriate technique for investigation of a patient with an abnormal IVU. Ultrasound is particularly useful in the investigation of children, pregnant women and patients with renal impairment. It can reliably differentiate solid masses from simple cysts, which are the most common space-occupying lesions in the kidney. A lesion that appears solid on ultrasound, or demonstrates any suspicious features, merits further analysis with CT or MRI.
  7. 7. Ultrasound is less accurate in staging renal cell carcinoma than CT or MRI. It is poor at demonstrating lymph node disease and skeletal or lung metastases.
  8. 8. When CT scanning is performed specifically to evaluate a known renal mass, the study must include an unenhanced examination prior to the administration of intravenous contrast material. By using a power injector, administer 150 mL of intravenous contrast material (75 mL for patients with a single kidney) injected at a minimum rate of 3 mL/sec to ensure that a high concentration of contrast material is present within the renal parenchyma during the post-contrast acquisition.
  9. 9. By using a multi–detector row CT scanner, contrast material– enhanced imaging is routinely performed during the corticomedullary and nephrographic phases of enhancement by using scanning delays of 40 and 100 seconds, respectively. The corticomedullary phase of enhancement is used to perform three-dimensional (3D) reconstructions and to depict the renal vasculature for urologists who perform laparoscopic nephrectomy. This phase is also useful to help differentiate a renal pseudotumor from a renal neoplasm
  10. 10. (A) Nephrotomogram of IVU demonstrates loss of the normal lateral contour of the left kidney and calyceal splaying. (B) Ultrasound demonstrates a homogeneous mass of reduced reflectivity
  11. 11. C. CT confirms the presence of an enhancing mass with a necrotic centre in keeping with a renal cell carcinoma.
  12. 12. Renal call carcinoma and inferior vena cava (IVC) tumour. Coronal MRI demonstrates a large tumour thrombus in the IVC in a patient with a large right-sided renal cell carcinoma.
  13. 13. Calcified renal cell carcinoma. (A) Ultrasound demonstrates a well- defined lesion in the upper pole of the right kidney with increased reflectivity. There is some minor posterior shadowing. (B) Intravenous urogram demonstrates a calcified peripheral mass in the kidney with no distortion of the calyceal system.
  14. 14. (C) CT before contrast administration demonstrates the lesion to be heavily calcified. (D) The lesion is almost completely obscured on the corticomedullary phase CT images, demonstrating the benefit of the precontrast images.
  15. 15. The ability of MRI to characterize renal masses has improved with the development of phased-array multicoils, fast breath- hold imaging and the use of gadolinium-DTPA contrast enhancement. Protocols vary widely but usually include pre- and postcontrast T1-weighted images with and without fat suppression. The coronal and sagittal planes are helpful for evaluating the extent of lesions. MR angiography can demonstrate the renal arteries and veins, and the inferior vena cava.
  16. 16. Although simple renal cysts and angiomyolipomas have characteristic appearances, the signal from most other masses is nonspecific. MRI is a good alternative to CT in patients with renal insufficiency or previous reactions to contrast medium and is superior to CT in differentiating benign thrombus from tumour thrombus and in identifying its extent. MRI is ideally suited for monitoring patients who have a genetically increased risk of renal malignancy, such as von Hippel–Lindau disease, who require regular follow-up. It is no more specific than CT at differentiating malignant from reactive lymphadenopathy
  17. 17. Renal arteriography is seldom used to diagnose or characterize a renal mass as the necessary information is usually provided by cross-sectional imaging. Angiography may very occasionally still have a role in preoperative planning when partial nephrectomy is being considered, although CT angiography or MR angiography can usually provide an adequate ‘road map’.
  18. 18. Percutaneous aspiration of renal cysts is indicated in the investigation of an indeterminate cystic renal mass, to diagnose an abscess or an infected cyst, and to confirm the presence of malignancy in a patient who is not a candidate for surgery. The aspirated fluid should be sent for cytological examination, although negative cytology does not exclude malignancy; this applies particularly in some cystic renal cell carcinomas, in which malignant disease is confined to the wall of the lesion. If the fluid is found to be turbid, microbiological examination should be performed.
  19. 19. A number of non-neoplastic tumours must be differentiated from renal cell carcinoma. Fetal lobulation occurs as a result of incomplete fusion of the fetal lobules, which results in a lobulated contour to the lateral border of the kidney, occurring between the underlying calices. Dromedary humps are bulges occurring on the lateral side of the left kidney. Many of these pseudotumours can be identified with ultrasound but occasionally further investigation is necessary. CT or radionuclide studies using 99mTc-DMSA can be useful. Normal variants are composed of functioning renal tissue and therefore exhibit excretion of isotope or contrast identical to the rest of the kidney.
  20. 20. This is the commonest form of cystic disease and is seen with increasing frequency with advancing age. On ultrasound examination renal cysts appear as anechoic, well- defined masses, with thin walls and good through transmission of sound. On CT a simple cyst usually appears as a well-defined rounded mass with an attenuation value of 0–20HU, with an imperceptible wall and no enhancement after injection of contrast medium. The MRI appearance of a simple renal cyst is characterized by a sharply demarcated, homogeneous, hypointense mass on T1- weighted images, which becomes uniformly hyperintense on T2- weighted images, and shows no enhancement following contrast medium administration.
  21. 21. A classification of cystic lesions was suggested in 1986 by Bosniak, based upon CT characteristics, and is used to guide management. Class I is a simple benign cyst. Class II cysts have one or more thin (< 1 mm) septa running through them, thin areas of mural calcification, or fluid contents of increased attenuation; they do not enhance following injection of contrast medium and are benign.
  22. 22. Class III cysts are more complicated and contain thickened septa, nodular areas of calcification, or solid nonenhancing areas. Such lesions are considered suggestive of malignancy and should be biopsied or surgically explored although fewer than half will turn out to be malignant. Class IV cystic masses are clearly malignant, with solid enhancing nodules or irregular walls, and should be treated accordingly. A subcategory, IIF, has been suggested for lesions with multiple class II features, and these require follow-up.
  23. 23. Ultrasound demonstrates a well- defined lesion with no internal echoes and enhanced through transmission. There are fine foci of linear calcification in the wall, making the lesion Bosniak class II. Bosniak class II cyst. Coronal post contrast CT. This complex cyst in the right kidney was difficult to evaluate in the axial plane and best examined in this coronal section.
  24. 24. Cystic renal cell carcinoma. (A) Precontrast image demonstrates a homogeneous low-attenuation mass in the left kidney. (B) Postcontrast image demonstrates a small peripheral nodule of enhancing tumour in the wall of the cyst (Bosniak class IV).
  25. 25. A simple benign cyst on ultrasound or CT requires no further follow-up. If there is wall thickening or the contents of the cyst are not of water density, the lesion is indeterminate. Haemorrhage or infection may result in cyst fluid of high attenuation but, unlike tumours, such lesions do not enhance following the administration of contrast medium. Ultrasound is helpful only if the hyperdense mass satisfies the ultrasound criteria of a benign simple cyst.
  26. 26. CT of haemorrhagic renal cyst. (A) Precontrast image reveals a high-density, round, smooth mass in the left kidney. (B) Following contrast medium there is no significant change in the appearance or density of the mass.
  27. 27. These occur in the renal sinus and frequently cause distortion, but rarely obstruction, of the renal collecting system. Peripelvic cysts are of lymphatic origin, whereas parapelvic cysts are renal serous cysts arising from the renal parenchyma that is present in the sinus. Although parapelvic cysts may be evaluated satisfactorily using ultrasound, peripelvic cysts can occasionally lead to confusion with hydronephrosis, as they track along the renal infundibula. Careful examination should demonstrate that the apparently dilated infundibula do not connect to a dilated renal pelvis. If necessary, urography or CT is usually confirmatory.
  28. 28. This is an autosomal dominant condition, which affects many organs in addition to the kidneys. Renal cysts are seen in addition to cysts within the liver, pancreas and spleen. Ultrasound demonstrates cysts in the adolescent or young adult, who is usually not yet clinically symptomatic. The full-blown disease presents with bilaterally enlarged kidneys with numerous cysts of varying sizes.
  29. 29. Occasionally, an infected cyst, a hyperdense cyst and, less commonly, a renal neoplasm may coexist with adult polycystic renal disease and the diagnosis becomes somewhat difficult in these cases. MRI may prove to be a useful technique in differentiating between simple cysts, haemorrhagic cysts and neoplasms when the findings on CT and ultrasound are equivocal.
  30. 30. ADPKD- CT delayed contrast and Fat sat T2 images showing hepatic and renal involvement.
  31. 31. This is a nonhereditary, congenital, usually unilateral form of renal cystic disease and is one of the commonest causes of an abdominal mass in the newborn.
  32. 32. This is characterised by presence of multiple cysts throughout or part or all of one kidney. Normal cortex is seen between the individual cysts as oppsed to multicystic renal dysplasia. The contralateral kidney is usually entirely normal and even if involved contains multiple tiny cysts , this feature helps to differentiate it from ADPKD. It is distinguished from multilocular cystic nephroma by the presence of normal parenchyma b/w the cysts,
  33. 33. CT scan slightly inferior to A shows multiple simple cysts separated by attenuated renal tissue (arrow).
  34. 34. They are thick-walled, mainly intrarenal and sometimes calcified . Hydatid cysts may present as flank or perinephric masses, which rupture into the collecting system, giving rise to acute flank pain followed by the voiding of hydatid scolices, with or without haematuria. Ultrasound demonstrates a multicystic lesion of mixed reflectivity.
  35. 35. Hydatid disease of the kidney. There is a cystic mass in the left kidney with a multiloculated internal appearance from the presence of many daughter cysts. The mass is causing marked pelvicalyceal dilatation.
  36. 36. Most abscesses are due to ascending infection, commonly by Escherichia coli. Immunocompromised and diabetic patients, as well as those with infected renal stones, are at a higher risk of developing renal infection. Haematogenous infection is usually secondary to Staphylococcus. Rupture of a renal abscess can lead to infection of the perinephric space.
  37. 37. CT is the best technique for the diagnosis and staging of renal and perinephric abscess. The central portion of an abscess is of near fluid density and does not demonstrate contrast enhancement, making it more obvious following contrast administration. There is often a thick irregular wall, which enhances together with inflammatory changes in the perinephric space. The presence of gas within a lesion is diagnostic of an abscess but is very rarely seen. The differential diagnosis of these appearances includes renal lymphoma, metastatic disease, renal infarction, and complicated cystic disease.
  38. 38. Renal abscess. CT demonstrates a poorly enhancing mass in the right kidney in a patient who had a severe urinary tract infection. The central fluid collection was aspirated and found to contain pus. The mass resolved completely after antibiotic therapy.
  39. 39. Focal pyelonephritis appears as a round or wedge-shaped focal mass without a defined wall, which tends to extend from the papilla to the outer cortex. The administration of contrast medium demonstrates heterogeneous enhancement of the affected area, which can often be greater than that of the normal parenchyma on delayed images. Perinephric inflammation is frequently seen. CT may demonstrate persistent renal abnormality for several weeks after infection and a focal mass may persist for several months.
  40. 40. This is a rare disease of the renal parenchyma caused by granulomatous inflammation. Malacoplakia is most commonly seen in middle-aged women and is more prevalent in individuals who are immunosuppressed. Renal involvement is usually associated with disease in the lower urinary tract. Focal hypoechoic renal masses may simulate renal abscesses, and heterogeneous masses that undergo calcification , may be mistaken for renal carcinoma. Renal malacoplakia can extend outside the kidney into the perinephric space and can also undergo spontaneous haemorrhage.
  41. 41. Renal haematoma may follow spontaneous intrarenal bleeding or occur as a result of trauma. It may be difficult to determine the cause. The ultrasound appearance of a haematoma varies according to its age. Fresh haematomas behave primarily as fluid collections, whereas organized haematomas may be highly reflective because they contain fragments of clot. CT during the acute phase will demonstrate an area of high attenuation, which is diagnostic of haematoma.
  42. 42. Two uncommon vascular lesions that may present as intrarenal masses are aneurysms and arteriovenous malformations (or fistulas). The former is usually caused by atherosclerosis, but may be congenital, post-traumatic, or secondary to vasculitis. Rim calcification is common. Arteriovenous communications are usually congenital, but may be caused by trauma (particularly renal biopsy) or atherosclerosis.
  43. 43. Angiomyolipomas are benign lesions composed of variable amounts of fat, smooth muscle and abnormal blood vessels. They occur mainly in women in the fifth decade. In patients with tuberous sclerosis they occur at a much younger age and are frequently multiple. Angiomyolipomas are composed of thick-walled, inelastic blood vessels. The risk of haemorrhage is related to the size of the tumour, and is significantly higher in lesions greater than 4 cm in diameter.
  44. 44. The appearance on ultrasound depends on the proportions of fat, smooth muscle and vascular elements, and on the presence of haemorrhage. Typically, angiomyolipoma appears as a circumscribed, highly reflective mass, more echogenic than the central sinus fat. Because of this high reflectivity, very tiny lesions can be detected with ultrasound. Tumours with a greater proportion of muscle, and those that have undergone haemorrhage or necrosis, may not be echogenic. Renal carcinomas smaller than 3 cm in diameter are also highly reflective, but the have a hyporeflective rim or small centeral hyporelective areas and unlike angiomyolipomas they don’t show posterior shadowing.
  45. 45. CT usually demonstrates a fatty mass intermixed with areas of increased tissue density, detection by CT of even a small amount of fat within a renal mass establishes the diagnosis of angiomyolipoma. If there is coexistent haemorrhage, CT and other techniques may not provide an accurate preoperative diagnosis. It is important to assess the relationship of the fat to the remainder of the tumour to be certain that the fat is intratumoral, and not peri renal fat that has been engulfed by an expanding renal cell carcinoma. Angiography can demonstrate multiple aneurysms and an ‘onion layer’ appearance. Embolization can control bleeding tumours and can also be used to treat enlarging tumours to reduce the risk of haemorrhage.
  46. 46. Multiple well defined homogeneously hyperechoic lesions with no perilesional halo in both left and right kidneys— Angiomyolipomas
  47. 47. USG (A) and color Doppler (B) show a small well-defined hyperechoic lesion in the right kidney with peripheral vascularity— Angiomyolipoma
  48. 48. Angiomyolipoma. Axial CT demonstrates small areas of fat within the right kidney consistent with an angiomyolipoma.
  49. 49. Bleeding angiomyolipoma. CT obtained following a severe attack of abdominal pain demonstrates perirenal blood and inflammatory change surrounding the right kidney following a spontaneous bleed. There is central fat density (arrow) which suggests the presence of an angiomyolipoma.
  50. 50. CECT showing large heterogeneous soft tissue masses in both kidneys with fat density scattered throughout and enlarged vessels—a case of tuberous sclerosis.
  51. 51. Sinus lipomatosis is an overabundance of normal renal sinus fat, which may produce stretching of the infundibula and compression of the renal pelvis, simulating a parapelvic cyst or other hilar renal mass. The diagnosis is generally made clear by CT or ultrasound. On ultrasound examination the area in question is usually echogenic.
  52. 52. Small renal tumours (< 3 cm) have been regarded in the past as adenomas rather than carcinomas. Unfortunately, the size of a renal mass is not a valid criterion for differentiating a benign from a malignant mass. There are reports of tumours that have produced metastases when less than 3 cm, although this is uncommon.
  53. 53. Oncocytomas are tubular adenomas with a specific histological appearance characterized by the oncocyte. Oncocytomas can occur at any age and are often asymptomatic at presentation. They can vary in size from 1 to 20 cm in diameter, but tend to be large. Although they are usually solitary and unilateral, they can be multiple (5%) and bilateral (3%). Ultrasound demonstrates a solid mass with internal echoes, which occasionally has a stellate hypoechoic centre. However, the echogenicity of the mass can be variable. Contrast-enhanced CT demonstrates a well-defined solid mass which, when large, can contain a low attenuation central scar.
  54. 54. Large lesions can extend into and engulf the perinephric fat, and can be mistaken for angiomyolipomas. There are no features on MRI that will differentiate an oncocytoma from renal carcinoma.
  55. 55. Oncocytoma. CT demonstrates multiple well-defined enhancing masses in both kidneys which were confirmed by percutaneous biopsy to be oncocytoma. Follow-up examination at 12 months did not demonstrate any growth.
  56. 56. Haemangiomas of the kidney are rare lesions that are generally cavernous rather than capillary. The most common symptom is haematuria. They are most commonly symptomatic in the middle years and are equally distributed between the sexes. Excretory urography may demonstrate a renal mass or, more commonly, pyelocalyceal distortion or a filling defect, attributable to the haemangioma or associated clot. Selective arteriography is often unhelpful, although occasionally will suggest the diagnosis.
  57. 57. This rare benign neoplasm presents as a unilateral septated encysted mass. It usually presents in young children but can be seen in adulthood, particularly in women. There are frequently septa which demonstrate enhancement. The cystic portion is usually of water density or slightly higher density with no enhancement. The best clue to the diagnosis is the presence of herniation of the mass into the renal hilum.
  58. 58. Renal cell carcinoma is the commonest renal malignancy, comprising 85% of all malignant renal tumours. It occurs bilaterally in 3–5% of cases. Most cases arise spontaneously in the fifth to seventh decade. Renal cell carcinoma is seen in about 36% of patients with von Hippel–Lindau disease . There is also an increased incidence of renal cell carcinoma in patients on long-term haemodialysis.
  59. 59. There are several main types as well as larger rare subtypes of RCC out of which important ones are. Clear cell carcinoma:- Commonest renal malignancy. Characterised by significant enhancement following contrast administration. Papillary tumours:- Commonly seen in failing kidneys and not infrequently multiple. Show minimal contrast enhancement and thus can be difficult to differentiate from a hyperdense cyst if precontrast not done. Chromophobe tumours:- Similar appearance as ocnocytomas with homogenous enhancement and presence of central scar. On USG appear as hyperechoic mass.
  60. 60. Plain radiographs show evidence of calcification in 5–10% of cases. IVU may demonstrate distortion of the calyceal system. Absence of contrast excretion is uncommon, and suggests tumour extension into the renal vein. Renal cell carcinoma can appear hyperechoic, hypoechoic, or isoechoic on ultrasound. Most small renal carcinomas are hyperechoic compared to normal parenchyma, whereas up to 86% of large tumours are isoechoic. Central necrosis can produce a central hypoechoic region that is associated with posterior acoustic enhancement. Cystic tumours may have thick or irregular walls together with small or large intracystic nodules of tumour. Ultrasound with colour Doppler is useful for detecting inferior vena cava thrombus and extension of tumour thrombus into the intrahepatic vena cava.
  61. 61. Renal cell carcinomas are often heterogeneous on unenhanced CT, with one or more low-density central areas. An extensively necrotic tumour may have a pseudocapsule. CT is the most sensitive technique for the depiction of parenchymal calcification associated with renal malignancy. Most renal cell cancers are solid, with attenuation values of more than 20HU on unenhanced CT images. An increase in attenuation of more than 10HU after administration of contrast medium suggests a solid mass, and enhancement of more than 20HU indicates malignancy
  62. 62. MRI can be used to detect and stage renal cell carcinoma, with a similar sensitivity to CT. The signal characteristics of renal cell carcinoma are variable, with tumours appearing isointense or hypointense compared to the renal cortex on T1-weighted sequences, and slightly hyperintense on T2- weighted sequences. Following administration of gadolinium, heterogeneous enhancement occurs immediately, decreasing on delayed images. Homogeneous enhancement is more likely in small, low-grade tumours. In most institutions CT is the technique of choice for the diagnosis and staging of renal cell cancer; MRI is used when contrast-enhanced CT is contraindicated, or if frequent follow-up is required in high-risk patients.
  63. 63. Disease extent TNM stage Tumour confined to kidney, small < 4 cm T1a Tumour confined to kidney > 4 cm, < 7 cm T1b Tumour confined to kidney > 7 cm T2 Tumour spread to perinephric fat T3a Tumour spread to renal vein or cava T3b Tumour spread to cava above diaphragm T3c Tumour spread outside Gerota's fascia T4 Metastasis in single lymph node N1 Metastasis in more than one lymph node N2 Distant metastasis M1
  64. 64. CT has a limited ability to identify lymph node involvement, based entirely on size. Using 1 cm as the upper limit of normal. Accurate identification of involvement of the renal vein and inferior vena cava is very important for correct patient management. Optimal enhancement of the renal vein is seen during the corticomedullary phase of enhancement. Thrombus is seen as a filling defect within the vein. It is usually difficult to differentiate tumour thrombus from bland thrombus unless enhancement can be seen within the thrombus. MRI is superior to CT in differentiating benign from malignant thrombus, but offers no advantage in staging nodal disease.
  65. 65. von Hippel–Lindau and T1 renal cell carcinoma. Coronal reconstruction demonstrates a T1 renal cell carcinoma in the lower pole of the right kidney which was not appreciated on the axial imaging. There is evidence of previous nephron- sparing surgery on the left side.
  66. 66. Papillary carcinoma. Pre- (A) and post- (B) contrast CT demonstrates a large poorly enhancing homogeneous mass seen in the left kidney that has the typical appearances of a papillary tumour. These have a relatively indolent course. Care must be taken not to diagnose these well-defined and homogeneous lesions as cysts.
  67. 67. Advanced renal cell carcinoma. Coronal postcontrast CT demonstrates tumour thrombus extending into the left renal vein but not into the cava (radiological stage T3b). The tumour was discovered when the patient presented with new onset of a varicocele.
  68. 68. A and B: Color Doppler: and spectral trace show vascularity within and surrounding the mass
  69. 69. A and B: NCCT and CECT showing a large enhancing left renal mass with peripheral and central coarse calcification in the left kidney
  70. 70. CT features of renal cell carcinomas in 4 phases: (A) Noncontrast, (B) Corticomedullary, (C) Nephrographic, (D) Excretory phases. Mass is best demarcated on nephrographic phase and shows “de-enhancement” in the later phase
  71. 71. Pre and post contrast images Shows solid left renal mass with increase in attenuation of 20 HU-malignant etiology (RCC)
  72. 72. Renal cell carcinoma – MRI (A) T2 coronal (B) T1W1 axial showing A well-circumscribed mass hypointense on T1 and hyperintense on T2 arising from upper pole of right kidney. IVC appears normal. Necrotic change is noted appearing hyperintense on T2W images
  73. 73. MRI—TRU FISP axial (A) and coronal (B) Mixed intensity right lower renal polar mass with areas of hemorrhage and well defined ‘pseudocapsule”
  74. 74. TI post gadolinium axial (C) and MPR (D) shows enhancing soft tissue component of the mass
  75. 75. Sarcomas of the kidney are rare, solid, malignant tumours, which develop from mesenchymal cells. Many of these tumours arise in close proximity to the renal capsule, making it difficult to distinguish whether they originate in the renal or perinephric tissues. The imaging characteristics are nonspecific, making it difficult to distinguish a renal sarcoma from a renal cell carcinoma. The tumours are frequently large at presentation and tend to present with abdominal pain and discomfort. Renal vein and inferior vena cava invasion are seen, and metastases are common at initial diagnosis.
  76. 76. Primary lymphoma of the kidney is very rare, as there is no lymphatic tissue within the kidneys. Renal involvement may be due to haematogenous spread or contiguous invasion from adjacent retroperitoneal lymphadenopathy. The kidneys are much more frequently involved in patients with non-Hodgkin's lymphoma, particularly when the disease has relapsed.
  77. 77. CT may demonstrate sheet-like diffuse infiltration of the perirenal tissues or multiple focal nodules. Following intravenous injection of contrast medium, focal lesions are usually of low attenuation. Contrast enhancement can also be useful in demonstrating the presence of discrete focal abnormalities in diffusely enlarged kidneys. Lymph node enlargement is often seen surrounding the vessels and can lead to bilateral hydronephrosis. Ga citrate radionuclide imaging may also identify lymphomatous involvement of the kidney. CT- or ultrasound- guided biopsy may be helpful if lymphoma is suspected.
  78. 78. Non-Hodgkin's lymphoma. (A) Unenhanced CT demonstrates homogeneous enlargement of both kidneys. (B) Postcontrast examination demonstrates multiple focal areas of reduced enhancement within the kidneys, consistent with lymphoma. Hepatic and pancreatic deposits of lymphoma can also be seen.
  79. 79. USG bilateral renal enlargement with poorly defined hypo/anechoic nodules giving a homogeneous appearance— lymphoma
  80. 80. Contrast enhanced CT showing well defined focal hypodense masses in both kidneys with significant retroperitoneal adenopathy and bowel thickening—a case of lymphoma
  81. 81. CT abdomen—bilateral kidneys are enlarged with loss of corticomedullary differentiation—a case of Burkitts lymphoma
  82. 82. These tumours rarely cause symptoms during life but are frequently found in autopsy studies. Most renal metastases are haematogenous, although a few occur by direct invasion or from lymphatic spread. The commonest primary tumours are bronchial, colorectal, breast, testicular and gynaecological malignancies, and malignant melanoma. Haematogenous metastases are usually small (< 3 cm), multiple and confined to the cortex. They are usually hypovascular on CT and do not tend to demonstrate calcification or renal vein invasion. Most metastases are more infiltrative and less exophytic than renal cell carcinoma.
  83. 83. Renal metastases from a leiomyosarcoma. (A) Several low attenuation lesions are seen in both kidneys in a patient with a past history of a pelvic leiomyosarcoma. (B) Coexistent local tumour recurrence in the left side of the pelvis.
  84. 84. MRI T1 vibe post contrast a focal poorly enhancing mass in the right kidney (A), Renal metastasis from disseminated ovarian malignancy (B)
  85. 85. TCC is the second most common renal neoplasm in adults. It is most common in urinary bladder, followed in frequency by ureter and pelvis. The incidence of TCC is more common in males, in the seventh decade. They commonly present with hematuria and flank pain. Hematogenous spread is less common than RCC, but lymphatic spread occurs earlier.
  86. 86. IVU The findings include a filling defect outlined by excreted contrast. The filling defect may be in pelvis (35%) or calyces (26%). ‘Stipple sign’ may be seen due to trapping of contrast in the interstices of a papillary growth. There may be obstruction of kidney with non opacification of the collecting system (phantom calyx) due to extensive areas of parenchymal infiltration. USG A large TCC is seen as an iso- to hypoechoic solid mass separating the central sinus echoes. A small TCC may not be detected on USG. Focal enlargement of renal cortex suggests infiltration of renal parenchyma. Longitudinal sonogram of the left kidney shows a solid lesion in the renal pelvis and upper ureter with consequent hydronephrosis - Transitional cell carcinoma
  87. 87. CT and MRI The most common appearance is of a small hypodense lesion in the renal collecting system, the lesion has a soft tissue attenuation (< 40 HU), less than most renal calculi, the attenuation of TCC is slightly lower than a blood clot, but higher than urine. TCC will enhance approx 10-50 HU, with the enhancement being less than renal parenchyma. This mild enhancement helps differentiate it from blood clot and calculi. In the kidney, TCC is usually more central than RCC, owing to the origin in the urothelium. The central mass expands the kidney symmetrically and with centrifugal extension preserves the shape.
  88. 88. TCC may present as a locally aggressive infiltrative renal mass, margins being ill defined. Involvement of renal parenchyma may be seen as a hypoenhancing mass involving parenchyma or heterogeneous abnormal hypoenhancement disrupting the normal parenchyma. MR appearance TCCs are typically isointense relative to renal medulla on T1WI on T2-weighted images seen as hypointense filling defects. Infitrative TCCs may be seen on single shot T2WI as intermediate signal intensity mass infiltrating the renal parenchyma. Enhancement of a focal filling defect in the collecting system is strongly suggestive of TCC. A cup-shaped dilatation of the ureter just distal to a focus of TCC in the ureter may be seen which is called as “chalice/goblet” sign.
  89. 89. MRI T2 coronal (A) T1, post- gadolinium axial (B) and coronal (C) shows an enhancing mass in the renal pelvis with hydronephrosis and retroperitoneal adenopathy— TCC
  90. 90. Squamous cell carcinoma of the renal pelvis is relatively rare tumor. It is highly aggressive, with a poor clinical prognosis. It often involves the renal parenchyma and perinephric tissue and may present with metastasis. In cross sectional imaging, this cannot be differentiated from transitional cell carcinomas. Pointers towards the diagnosis of SCC include the fact that SCC grow fast, and rapid progression on sequential studies favour SCC.