HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Full Text (PDF) CME Test (opens in a new window) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Rha, S. E. Articles by Lee, J. M. Search for Related Content PubMed PubMed Citation Articles by Rha, S. E. Articles by Lee, J. M. Related Collections Genitourinary Radiology

The Renal Sinus: Pathologic Spectrum and Multimodality Imaging Approach¹

¹ From the Departments of Radiology (S.E.R., J.Y.B., S.E.J., S.N.O., J.M.L.) and Pathology (Y.J.C., A.L.), College of Medicine, Catholic University of Korea, 505 Banpo-Dong, Seocho-Ku, Seoul 137-040, South Korea. Recipient of a Cum Laude award for an education exhibit at the 2003 RSNA scientific assembly. Received February 4, 2004; revision requested April 2 and received May 7; accepted May 12. All authors have no financial relationships to disclose. Address correspondence to J.Y.B. (e-mail: jybyun@catholic.ac.kr).

View larger version (64K): [in a new window]   Figure 1.  Diagram shows the normal anatomy and major constituents of the renal sinus. Note that fat is the largest component of the renal sinus. IVC = inferior vena cava.

View larger version (158K): [in a new window]   Figure 2.  Normal computed tomographic (CT) anatomy of the renal sinus. Coronal contrast material-enhanced CT scan obtained during the excretory phase shows the extent of the renal sinus (arrowheads).

View larger version (128K): [in a new window]   Figure 3a.  Bilateral renal sinus lipomatosis in a 76-year-old asymptomatic man. (a) Excretory urogram shows diffuse elongation and attenuation of the renal pelvis and infundibula of both kidneys. (b) Axial contrast-enhanced CT scan shows proliferation of fat (arrows) in both renal sinuses, a finding suggestive of renal sinus lipomatosis.

View larger version (149K): [in a new window]   Figure 3b.  Bilateral renal sinus lipomatosis in a 76-year-old asymptomatic man. (a) Excretory urogram shows diffuse elongation and attenuation of the renal pelvis and infundibula of both kidneys. (b) Axial contrast-enhanced CT scan shows proliferation of fat (arrows) in both renal sinuses, a finding suggestive of renal sinus lipomatosis.

View larger version (138K): [in a new window]   Figure 4a.  Replacement lipomatosis of the renal sinus and periureteral space in a 63-year-old man with chronic renal calculus disease. A percutaneous nephrostomy tube was inserted for stone extraction. CT was performed because procedure-related hemorrhage was suspected. (a) Axial contrast-enhanced CT scan shows a tumorlike mass of fat (arrows) that occupies the left renal sinus and surrounds the left ureter (u). The left renal parenchyma is markedly atrophied in association with a large stone (arrowhead), and a large amount of subcapsular hematoma (H) is also seen. Note the percutaneous nephrostomy tube. (b) Photograph of the surgical specimen shows the markedly atrophied kidney (arrows) containing several stones; the kidney is surrounded by fatty tissue (F).

View larger version (82K): [in a new window]   Figure 4b.  Replacement lipomatosis of the renal sinus and periureteral space in a 63-year-old man with chronic renal calculus disease. A percutaneous nephrostomy tube was inserted for stone extraction. CT was performed because procedure-related hemorrhage was suspected. (a) Axial contrast-enhanced CT scan shows a tumorlike mass of fat (arrows) that occupies the left renal sinus and surrounds the left ureter (u). The left renal parenchyma is markedly atrophied in association with a large stone (arrowhead), and a large amount of subcapsular hematoma (H) is also seen. Note the percutaneous nephrostomy tube. (b) Photograph of the surgical specimen shows the markedly atrophied kidney (arrows) containing several stones; the kidney is surrounded by fatty tissue (F).

View larger version (184K): [in a new window]   Figure 5a.  Renal sinus cysts in a 53-year-old asymptomatic man. (a) Axial contrast-enhanced CT scan obtained during the nephrographic phase shows low-attenuation cystic lesions (arrows) in the left renal sinus; this finding could be misinterpreted as hydronephrosis. (b) Axial contrast-enhanced CT scan obtained during the excretory phase shows the cysts (arrows) in the renal sinus, an appearance different from that of hydronephrosis. The enhanced calices are stretched and attenuated but not obstructed by the cysts.

View larger version (159K): [in a new window]   Figure 5b.  Renal sinus cysts in a 53-year-old asymptomatic man. (a) Axial contrast-enhanced CT scan obtained during the nephrographic phase shows low-attenuation cystic lesions (arrows) in the left renal sinus; this finding could be misinterpreted as hydronephrosis. (b) Axial contrast-enhanced CT scan obtained during the excretory phase shows the cysts (arrows) in the renal sinus, an appearance different from that of hydronephrosis. The enhanced calices are stretched and attenuated but not obstructed by the cysts.

View larger version (134K): [in a new window]   Figure 6a.  Renal sinus cyst in a 54-year-old asymptomatic man. (a) Excretory urogram shows splaying of the calices and compression of the right renal pelvis (arrows), findings suggestive of a focal lesion. (b) Axial contrast-enhanced CT scan shows a single, well-defined, water-attenuation cyst (arrows) protruding into the renal sinus. It has the same appearance as the more common renal cortical cyst (arrowhead).

View larger version (180K): [in a new window]   Figure 6b.  Renal sinus cyst in a 54-year-old asymptomatic man. (a) Excretory urogram shows splaying of the calices and compression of the right renal pelvis (arrows), findings suggestive of a focal lesion. (b) Axial contrast-enhanced CT scan shows a single, well-defined, water-attenuation cyst (arrows) protruding into the renal sinus. It has the same appearance as the more common renal cortical cyst (arrowhead).

View larger version (164K): [in a new window]   Figure 7.  Renal artery aneurysm in a 47-year-old man with gross hematuria. Coronal reformatted CT scan obtained during the corticomedullary phase shows a small saccular aneurysm (arrow) in the right renal sinus.

View larger version (109K): [in a new window]   Figure 8a.  Partially thrombosed renal artery aneurysm with rim calcification in a 67-year-old man with hypertension. (a) Axial unenhanced CT scan shows a large, lobulated, masslike lesion with soft-tissue attenuation and rim calcifications (arrows) in the right renal sinus. (b) Axial contrast-enhanced CT scan shows that the lesion is vascular (arrows) with a nonenhancing area suggestive of thrombus (T). (c) Direct right renal arteriogram shows the large, saccular, bilobed aneurysm.

View larger version (141K): [in a new window]   Figure 8b.  Partially thrombosed renal artery aneurysm with rim calcification in a 67-year-old man with hypertension. (a) Axial unenhanced CT scan shows a large, lobulated, masslike lesion with soft-tissue attenuation and rim calcifications (arrows) in the right renal sinus. (b) Axial contrast-enhanced CT scan shows that the lesion is vascular (arrows) with a nonenhancing area suggestive of thrombus (T). (c) Direct right renal arteriogram shows the large, saccular, bilobed aneurysm.

View larger version (118K): [in a new window]   Figure 8c.  Partially thrombosed renal artery aneurysm with rim calcification in a 67-year-old man with hypertension. (a) Axial unenhanced CT scan shows a large, lobulated, masslike lesion with soft-tissue attenuation and rim calcifications (arrows) in the right renal sinus. (b) Axial contrast-enhanced CT scan shows that the lesion is vascular (arrows) with a nonenhancing area suggestive of thrombus (T). (c) Direct right renal arteriogram shows the large, saccular, bilobed aneurysm.

View larger version (123K): [in a new window]   Figure 9a.  Renal arteriovenous fistula in a 48-year-old woman with sudden onset of hematuria and right flank pain. Excretory urography performed 3 days before retrograde pyelography showed nonopacification of the right kidney. (a) Retrograde pyelogram shows nonopacification of the lower pole calices and irregular tortuous filling defects in and around the interpolar calices and pelvis (arrows). The pelvicaliceal system is mildly dilated. (b) Axial contrast-enhanced CT scan obtained during the corticomedullary phase shows tortuous, dilated, enhancing vascular structures (arrow) in the right renal sinus. Note the mildly dilated right renal pelvis and the double-J catheter (arrowhead) in the renal pelvis. (c) Coronal contrast-enhanced T1-weighted MR image (repetition time msec/echo time msec = 111/4.1) shows the tortuous vascular structures with signal void (arrows) along the dilated collecting system. (d) Right renal arteriogram shows the entangled vessels of the arteriovenous communication (arrows), which is sometimes referred to as a cirsoid aneurysm, in the lower polar area of the right kidney.

View larger version (118K): [in a new window]   Figure 9b.  Renal arteriovenous fistula in a 48-year-old woman with sudden onset of hematuria and right flank pain. Excretory urography performed 3 days before retrograde pyelography showed nonopacification of the right kidney. (a) Retrograde pyelogram shows nonopacification of the lower pole calices and irregular tortuous filling defects in and around the interpolar calices and pelvis (arrows). The pelvicaliceal system is mildly dilated. (b) Axial contrast-enhanced CT scan obtained during the corticomedullary phase shows tortuous, dilated, enhancing vascular structures (arrow) in the right renal sinus. Note the mildly dilated right renal pelvis and the double-J catheter (arrowhead) in the renal pelvis. (c) Coronal contrast-enhanced T1-weighted MR image (repetition time msec/echo time msec = 111/4.1) shows the tortuous vascular structures with signal void (arrows) along the dilated collecting system. (d) Right renal arteriogram shows the entangled vessels of the arteriovenous communication (arrows), which is sometimes referred to as a cirsoid aneurysm, in the lower polar area of the right kidney.

View larger version (155K): [in a new window]   Figure 9c.  Renal arteriovenous fistula in a 48-year-old woman with sudden onset of hematuria and right flank pain. Excretory urography performed 3 days before retrograde pyelography showed nonopacification of the right kidney. (a) Retrograde pyelogram shows nonopacification of the lower pole calices and irregular tortuous filling defects in and around the interpolar calices and pelvis (arrows). The pelvicaliceal system is mildly dilated. (b) Axial contrast-enhanced CT scan obtained during the corticomedullary phase shows tortuous, dilated, enhancing vascular structures (arrow) in the right renal sinus. Note the mildly dilated right renal pelvis and the double-J catheter (arrowhead) in the renal pelvis. (c) Coronal contrast-enhanced T1-weighted MR image (repetition time msec/echo time msec = 111/4.1) shows the tortuous vascular structures with signal void (arrows) along the dilated collecting system. (d) Right renal arteriogram shows the entangled vessels of the arteriovenous communication (arrows), which is sometimes referred to as a cirsoid aneurysm, in the lower polar area of the right kidney.

View larger version (126K): [in a new window]   Figure 9d.  Renal arteriovenous fistula in a 48-year-old woman with sudden onset of hematuria and right flank pain. Excretory urography performed 3 days before retrograde pyelography showed nonopacification of the right kidney. (a) Retrograde pyelogram shows nonopacification of the lower pole calices and irregular tortuous filling defects in and around the interpolar calices and pelvis (arrows). The pelvicaliceal system is mildly dilated. (b) Axial contrast-enhanced CT scan obtained during the corticomedullary phase shows tortuous, dilated, enhancing vascular structures (arrow) in the right renal sinus. Note the mildly dilated right renal pelvis and the double-J catheter (arrowhead) in the renal pelvis. (c) Coronal contrast-enhanced T1-weighted MR image (repetition time msec/echo time msec = 111/4.1) shows the tortuous vascular structures with signal void (arrows) along the dilated collecting system. (d) Right renal arteriogram shows the entangled vessels of the arteriovenous communication (arrows), which is sometimes referred to as a cirsoid aneurysm, in the lower polar area of the right kidney.

View larger version (163K): [in a new window]   Figure 10a.  Renal aspergillosis in an 18-year-old man with acute myeloid leukemia who presented with fever and left flank pain. (a) Axial unenhanced CT scan shows a lobulated masslike lesion (arrows) with focal internal high attenuation, a finding suggestive of intralesion hemorrhage. (b) Coronal reformatted contrast-enhanced CT scan obtained during the excretory phase shows the poorly enhancing, low-attenuation, masslike renal parenchymal lesion extending to the renal sinus (arrow). Analysis of the nephrectomy specimen demonstrated a hemorrhagic mass due to focal invasive aspergillosis. Aspergillosis causes vascular occlusion and multiple renal infarcts. However, as in this case, differentiation from a tumor is not always easy.

View larger version (169K): [in a new window]   Figure 10b.  Renal aspergillosis in an 18-year-old man with acute myeloid leukemia who presented with fever and left flank pain. (a) Axial unenhanced CT scan shows a lobulated masslike lesion (arrows) with focal internal high attenuation, a finding suggestive of intralesion hemorrhage. (b) Coronal reformatted contrast-enhanced CT scan obtained during the excretory phase shows the poorly enhancing, low-attenuation, masslike renal parenchymal lesion extending to the renal sinus (arrow). Analysis of the nephrectomy specimen demonstrated a hemorrhagic mass due to focal invasive aspergillosis. Aspergillosis causes vascular occlusion and multiple renal infarcts. However, as in this case, differentiation from a tumor is not always easy.

View larger version (134K): [in a new window]   Figure 11a.  Transitional cell carcinoma of the renal pelvis in a 65-year-old man with a 1-month history of left flank pain and intermittent gross hematuria. (a) Axial contrast-enhanced CT scan obtained during the nephrographic phase shows an ill-defined low-attenuation mass (arrow) in the central portion of the left kidney. (b) Coronal maximum intensity projection CT scan obtained during the excretory phase shows a large filling defect with an irregular margin (arrows) in the pelvicalices of the left kidney, thus clearly demonstrating the extent of the tumor.

View larger version (98K): [in a new window]   Figure 11b.  Transitional cell carcinoma of the renal pelvis in a 65-year-old man with a 1-month history of left flank pain and intermittent gross hematuria. (a) Axial contrast-enhanced CT scan obtained during the nephrographic phase shows an ill-defined low-attenuation mass (arrow) in the central portion of the left kidney. (b) Coronal maximum intensity projection CT scan obtained during the excretory phase shows a large filling defect with an irregular margin (arrows) in the pelvicalices of the left kidney, thus clearly demonstrating the extent of the tumor.

View larger version (104K): [in a new window]   Figure 12a.  Squamous cell carcinoma in a 50-year-old man with chronic calculus disease and left flank pain. (a) Axial unenhanced CT scan shows a high-attenuation stone (arrow) in the left renal pelvis. A tiny amount of air (arrowhead) due to previously performed percutaneous nephrostomy is seen in the renal sinus. (b) Axial contrast-enhanced CT scan obtained during the excretory phase shows an infiltrative mass (arrows) in the renal pelvis that extends to the renal parenchyma. Note the metastatic lymph nodes (arrowhead) in the paraaortic space.

View larger version (113K): [in a new window]   Figure 12b.  Squamous cell carcinoma in a 50-year-old man with chronic calculus disease and left flank pain. (a) Axial unenhanced CT scan shows a high-attenuation stone (arrow) in the left renal pelvis. A tiny amount of air (arrowhead) due to previously performed percutaneous nephrostomy is seen in the renal sinus. (b) Axial contrast-enhanced CT scan obtained during the excretory phase shows an infiltrative mass (arrows) in the renal pelvis that extends to the renal parenchyma. Note the metastatic lymph nodes (arrowhead) in the paraaortic space.

View larger version (139K): [in a new window]   Figure 13a.  Venous hemangioma of the renal sinus in a 33-year-old man with gross hematuria and left flank pain. (a) Axial unenhanced CT scan shows a well-defined high-attenuation lesion (arrows) adjacent to the left renal pelvis. (b) Axial contrast-enhanced CT scan shows that the mass (arrows) has low attenuation and poor enhancement. Because of the possibility of malignancy, left nephrectomy was performed. At pathologic examination, the lesion was composed of multiple vascular channels of variable sizes beneath the pelvic mucosa. Renal hemangioma is seldom diagnosed preoperatively but should be included in the differential diagnosis when CT demonstrates poor enhancement of a renal mass located at the pelvicaliceal junction or in the inner medulla. (Reprinted, with permission, from reference 22.)

View larger version (127K): [in a new window]   Figure 13b.  Venous hemangioma of the renal sinus in a 33-year-old man with gross hematuria and left flank pain. (a) Axial unenhanced CT scan shows a well-defined high-attenuation lesion (arrows) adjacent to the left renal pelvis. (b) Axial contrast-enhanced CT scan shows that the mass (arrows) has low attenuation and poor enhancement. Because of the possibility of malignancy, left nephrectomy was performed. At pathologic examination, the lesion was composed of multiple vascular channels of variable sizes beneath the pelvic mucosa. Renal hemangioma is seldom diagnosed preoperatively but should be included in the differential diagnosis when CT demonstrates poor enhancement of a renal mass located at the pelvicaliceal junction or in the inner medulla. (Reprinted, with permission, from reference 22.)

View larger version (132K): [in a new window]   Figure 14a.  Leiomyoma of the renal sinus in a 28-year-old woman with gross hematuria. (a) Excretory urogram shows focal smooth mass effect on the pelvicalices of the right kidney (arrows). (b) Axial contrast-enhanced CT scan obtained during the nephrographic phase shows a small mass (arrow) with soft-tissue attenuation obliterating the fat in the right renal sinus along the posterior margin of the renal pelvis. (c) Coronal reformatted CT scan shows the round soft-tissue attenuation mass (arrow) in the right renal sinus and mild dilatation of the pelvicaliceal system. (d) Photograph of the surgical specimen shows the well-defined round mass (arrows) in the renal sinus. Microscopic examination demonstrated a renal leiomyoma.

View larger version (126K): [in a new window]   Figure 14b.  Leiomyoma of the renal sinus in a 28-year-old woman with gross hematuria. (a) Excretory urogram shows focal smooth mass effect on the pelvicalices of the right kidney (arrows). (b) Axial contrast-enhanced CT scan obtained during the nephrographic phase shows a small mass (arrow) with soft-tissue attenuation obliterating the fat in the right renal sinus along the posterior margin of the renal pelvis. (c) Coronal reformatted CT scan shows the round soft-tissue attenuation mass (arrow) in the right renal sinus and mild dilatation of the pelvicaliceal system. (d) Photograph of the surgical specimen shows the well-defined round mass (arrows) in the renal sinus. Microscopic examination demonstrated a renal leiomyoma.

View larger version (141K): [in a new window]   Figure 14c.  Leiomyoma of the renal sinus in a 28-year-old woman with gross hematuria. (a) Excretory urogram shows focal smooth mass effect on the pelvicalices of the right kidney (arrows). (b) Axial contrast-enhanced CT scan obtained during the nephrographic phase shows a small mass (arrow) with soft-tissue attenuation obliterating the fat in the right renal sinus along the posterior margin of the renal pelvis. (c) Coronal reformatted CT scan shows the round soft-tissue attenuation mass (arrow) in the right renal sinus and mild dilatation of the pelvicaliceal system. (d) Photograph of the surgical specimen shows the well-defined round mass (arrows) in the renal sinus. Microscopic examination demonstrated a renal leiomyoma.

View larger version (137K): [in a new window]   Figure 14d.  Leiomyoma of the renal sinus in a 28-year-old woman with gross hematuria. (a) Excretory urogram shows focal smooth mass effect on the pelvicalices of the right kidney (arrows). (b) Axial contrast-enhanced CT scan obtained during the nephrographic phase shows a small mass (arrow) with soft-tissue attenuation obliterating the fat in the right renal sinus along the posterior margin of the renal pelvis. (c) Coronal reformatted CT scan shows the round soft-tissue attenuation mass (arrow) in the right renal sinus and mild dilatation of the pelvicaliceal system. (d) Photograph of the surgical specimen shows the well-defined round mass (arrows) in the renal sinus. Microscopic examination demonstrated a renal leiomyoma.

View larger version (122K): [in a new window]   Figure 15a.  Leiomyosarcoma of the renal sinus in a 65-year-old woman with left flank pain and a palpable left abdominal mass. (a) Axial contrast-enhanced CT scan shows a large mass (arrows) with heterogeneous attenuation expanding the left renal sinus. The renal parenchyma (P) is markedly compressed and displaced laterally. (b) Coronal turbo spin-echo T2-weighted MR image (6,500/120) shows the location and extent of the tumor (arrows). P = renal parenchyma. (c) Photograph of the surgical specimen shows the relatively well-defined tumor (arrows) (13 x 9 x 8 cm) in the renal sinus. The tumor has a solid and compact cut surface with central hemorrhage and necrosis. It is confined to the sinus and does not invade the renal parenchyma (P) or pelvis. The adjacent renal parenchyma is compressed by the tumor.

View larger version (142K): [in a new window]   Figure 15b.  Leiomyosarcoma of the renal sinus in a 65-year-old woman with left flank pain and a palpable left abdominal mass. (a) Axial contrast-enhanced CT scan shows a large mass (arrows) with heterogeneous attenuation expanding the left renal sinus. The renal parenchyma (P) is markedly compressed and displaced laterally. (b) Coronal turbo spin-echo T2-weighted MR image (6,500/120) shows the location and extent of the tumor (arrows). P = renal parenchyma. (c) Photograph of the surgical specimen shows the relatively well-defined tumor (arrows) (13 x 9 x 8 cm) in the renal sinus. The tumor has a solid and compact cut surface with central hemorrhage and necrosis. It is confined to the sinus and does not invade the renal parenchyma (P) or pelvis. The adjacent renal parenchyma is compressed by the tumor.

View larger version (137K): [in a new window]   Figure 15c.  Leiomyosarcoma of the renal sinus in a 65-year-old woman with left flank pain and a palpable left abdominal mass. (a) Axial contrast-enhanced CT scan shows a large mass (arrows) with heterogeneous attenuation expanding the left renal sinus. The renal parenchyma (P) is markedly compressed and displaced laterally. (b) Coronal turbo spin-echo T2-weighted MR image (6,500/120) shows the location and extent of the tumor (arrows). P = renal parenchyma. (c) Photograph of the surgical specimen shows the relatively well-defined tumor (arrows) (13 x 9 x 8 cm) in the renal sinus. The tumor has a solid and compact cut surface with central hemorrhage and necrosis. It is confined to the sinus and does not invade the renal parenchyma (P) or pelvis. The adjacent renal parenchyma is compressed by the tumor.

View larger version (160K): [in a new window]   Figure 16.  Hemangiopericytoma of the renal sinus in a 30-year-old woman with generalized weakness. Axial contrast-enhanced CT scan shows a large, well-defined mass (M) with soft-tissue attenuation occupying the central portion of the left renal sinus and compressing the enhanced pelvicaliceal system. (Reprinted, with permission, from reference 31.)

View larger version (156K): [in a new window]   Figure 17.  Extension of renal cell carcinoma into the renal sinus in a 51-year-old man with gross hematuria. Coronal reformatted contrast-enhanced CT scan obtained during the excretory phase shows tumor involvement of the renal sinus and the extent of the renal cell carcinoma (arrows). The pathologic stage was T3b N0.

View larger version (108K): [in a new window]   Figure 18a.  Multilocular cystic nephroma in a 32-year-old man. (a) Excretory urogram shows marked splaying of the upper and lower caliceal systems (arrows) with mild dilatation of the upper pole calix. (b) Axial MR image obtained with true fast imaging with steady-state precession (6.3/3.0, 70° flip angle) shows a high-signal-intensity cystic mass in the left kidney. Note the numerous fine septations without solid components. (c) Coronal gadolinium-enhanced T1-weighted MR image (130/4.1) shows herniation of the cystic mass (arrow) into the renal sinus.

View larger version (110K): [in a new window]   Figure 18b.  Multilocular cystic nephroma in a 32-year-old man. (a) Excretory urogram shows marked splaying of the upper and lower caliceal systems (arrows) with mild dilatation of the upper pole calix. (b) Axial MR image obtained with true fast imaging with steady-state precession (6.3/3.0, 70° flip angle) shows a high-signal-intensity cystic mass in the left kidney. Note the numerous fine septations without solid components. (c) Coronal gadolinium-enhanced T1-weighted MR image (130/4.1) shows herniation of the cystic mass (arrow) into the renal sinus.

View larger version (138K): [in a new window]   Figure 18c.  Multilocular cystic nephroma in a 32-year-old man. (a) Excretory urogram shows marked splaying of the upper and lower caliceal systems (arrows) with mild dilatation of the upper pole calix. (b) Axial MR image obtained with true fast imaging with steady-state precession (6.3/3.0, 70° flip angle) shows a high-signal-intensity cystic mass in the left kidney. Note the numerous fine septations without solid components. (c) Coronal gadolinium-enhanced T1-weighted MR image (130/4.1) shows herniation of the cystic mass (arrow) into the renal sinus.

View larger version (155K): [in a new window]   Figure 19.  Lymphoma involving the renal parenchyma and renal sinus in a 56-year-old man with generalized weakness. Coronal reformatted CT scan obtained during the nephrographic phase shows a large, relatively homogeneous retroperitoneal mass (arrows) extending to the renal sinus and mild hydronephrosis of the right kidney.

View larger version (169K): [in a new window]   Figure 20.  Metastatic lymphadenopathy in the renal sinus from colon cancer in a 57-year-old man. Axial contrast-enhanced CT scan shows a soft-tissue attenuation mass (arrows) in the right renal sinus with obstructive hydronephrosis.