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Solid Processes. RCC-invasion of perirenal fat, thickening of renal fascia . Renal cell carcinoma is the most common malignancy of the kidney and accounts for 2% of all cancers. Lymphoma - multiple renal masses, contiguous retroperitoneal masses, perirenal masses, single renal mass
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Solid Processes • RCC-invasion of perirenal fat, thickening of renal fascia.Renal cell carcinoma is the most common malignancy of the kidney and accounts for 2% of all cancers. • Lymphoma-multiple renal masses, contiguous retroperitoneal masses, perirenal masses, single renal mass • Metastasis-to perirenal lymphatics - melanoma, RCC, lung (via pleura/mediastinal connections) • Fibrosis-AO, IVC, ureters, perinephric space • Amyloidosis-perirenal soft tissue collections
Renal cell carcinoma (RCC) • is the most common primary renal malignant neoplasm in the adult. It accounts for approximately 85% of renal tumors and 2% of all adult malignancies. • RCC is more common in men than in women (ratio, 2:1), and it most often occurs in patients aged 50-70 years. • One fourth to one third of patients have metastatic disease at the time of presentation. • In only approximately 2% of sporadic cases are bilateral tumors seen at presentation.
RCC risk factors include • increased age, male sex, smoking, cadmium, benzene, trichloroethylene and asbestos exposure, excessive weight, chronic dialysis use, and several genetic syndromes (familial RCC, hereditary papillary RCC, von Hippel-Lindau syndrome, and tuberous sclerosis)
Renal Cell Carcinoma with Spread to Gerota’s Fascia
MRI of the Kidneys • When contraindication to IV contrast • Renal mass characterization • Staging renal cell carcinoma • Vascular involvement
Renal cell carcinoma • MRI better than CT in demonstrating vascular invasion • Renal vein • IVC
Tumor Tumor Axial Coronal Renal Cell Carcinoma with tumor invading right renal vein and IVC Tumor Axial
Retroperitoneal Lymphoma • Lymphadenopathy- can directly invade kidney or encase ureter • Perirenal involvement- transcapsular, direct spread from lymph nodes, isolated disease (least common)
Lymphoma involving the small bowel mesentery, anterior pararenal space, perinephric space and kidneys
Metastatic Lung Cancer
Adrenal Metastasis Perinephric Metastasis
Renal Infarction • Causes • Embolism (cardiac) • Aortic dissection • Trauma • Venous thrombosis (dehydration, tumor)
Renal InfarctionCT Findings (with IV contrast) • Focal • Region of no enhancement • Diffuse • Hypodense kidney • Renal enlargement • May see rim of enhancement • Patent collateral capsular vessels
Two contrast-enhanced axial CT images demonstrate a wedge-shapednon-enhancing lesion in the right kidney with no perinephric inflammatory stranding
History atrial fibrillation, presents with right flank pain Left atrial thrombus Renal infarct
Right Flank Pain Renal tumor IVC Renal infarct
Presents with left flank pain Pyonephrosis —gas in infected collecting system
Patient Presents with Right Flank Pain Kidney normal Cholecystitis Gallstone in distended GB
2 Different Patients with Right Flank Pain Dermoids Ovarian cyst
CRF: Prominent bridging septae and small amount of perinephric fluid
Kidney “sweat sign” Fluid in perirenal space corresponding to thickened septae and fluid on CT scan Echogenic kidneys in patient with CRF
Acute Pancreatitis Inflammatory process spares perinephric spaces
Acute hemorrhage in anterior pararenal space involves perinephric space via septae
Lymphatic Spread of Diseasefrom Perinephric Space • Small perirenal lymph nodes • • Nodes in renal hilum • • Periaortic/pericaval nodes
Inflammatory Processes and Fluid Collections • Infections • Urinomas • Hematomas • Pseudocysts
Infections • Most originate from kidney • May spread through all spaces and via bare area to peritoneum and thorax • Xanthogranulomatous pyelonephritis
Subcapsular Abscess
Chronic Perinephric Abscess Abscess is loculated in perinephric space secondary to perinephric septae. See also calculus and mild hydronephrosis
Pyelonephritis in Ectopic Kidneys Adrenal Level Renal Level Note straight adrenal glands with liver, spleen and colon falling into expected renal fossae. At level of pancake kidney, renal fascia is visualized and slightly thickened.
Perinephric gas extending to extraperitoneal space and to anterior abdominal wall muscles. Patient with fever after left hemicolectomy
Xanthogranulomatous Pyelonephritis Obstructed upper pole Extension to post pararenal space and post abd wall
Hematomas • Traumatic- MVA, iatrogenic • Spontaneous- tumor, vascular (AAA, AVM, arteritis), hematologic disorders, endstage kidney • Spread of hepatic or splenic hematomas to perinephric space without renal injury • Leaking aortic aneurysm
Subcapsular into anterior pararenal space extending along iliac vessels into pelvis.Also via perinephric septae to upper aspect post pararenal space Spontaneous Hemorrhage in End-stage Kidney
Subcapsular to perinephric to anterior pararenal hematoma secondary to renal artery stent placement ATN with vicarious gallbladder excretion
Renal Cell Carcinoma with spontaneous hemorrhage
Traumatic Avulsion Renal Artery RRA with perinephric hematoma
Retroperitoneal Fibrosis • Most commonly idiopathic • Other causes: aortic hemorrhage, aortitis, methysergide toxicity, prior surgery or XRT, collagen vascular disease (Riedel’s thyroiditis, sclerosing mediastinitis) • Clinical: 40-60 yrs, males>females • Hydronephrosis, ureteral narrowing, slight medial ureteral displacement
Retroperitoneal Fibrosis extending into perinephric and postpararenal spaces
MRI of the Adrenal Glands • Metastases versus non-functioning adenoma • Suspected pheochromocytoma • Helpful to localize origin of mass discovered on CT/US • Upper pole kidney vs adrenal gland
Is this mass arising from the liver, kidney or adrenal gland?
Coronal imaging shows mass not renal in origin Adrenal tumor invading liver
Adrenal Masses • Adenomas are very common • 2-8% of population • Metastases are common in adrenal glands • Fortunately, MR can accurately distinguish between adenomas and metastases
Adrenal Adenomas • Key to diagnosis is demonstrating fat/lipid in mass • Chemical shift imaging • Fat suppression imaging
MRI of adrenal adenomas • High lipid content • Chemical shift imaging helpful • In-phase: bright • Out-of-phase: dark • Look for “india ink” rim at fat/water interface