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Renal Masses. Robert D. Thomas MD Pediatric Radiology. Balls Cyst Hematoma Abscess Tumor Dromedary hump. Beans Duplication/anomaly Compensatory hypertrophy Hydronephrosis Pyelonephritis/edema Hematoma PCKD Tumor Vascular occlusion/trauma. Renal Masses. Newborn Hydronephrosis
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Renal Masses Robert D. Thomas MD Pediatric Radiology
Balls Cyst Hematoma Abscess Tumor Dromedary hump Beans Duplication/anomaly Compensatory hypertrophy Hydronephrosis Pyelonephritis/edema Hematoma PCKD Tumor Vascular occlusion/trauma Renal Masses
Newborn Hydronephrosis MCDK AR-PCKD Anomalies Tumors Mesoblastic nephroma Nephroblastomatosis Childhood Cysts Hydronephrosis, MCDK Anomalies Hematoma Tumors Wilms Lymphoma Angiomyolipomas Renal Masses by Age
Hydronephrosis(Bean) • Calyceal/Pelvic obstruction • Congenital (intrinsic/extrinsic) • TB • Tumor • Ureter • Physiologic (full bladder) • Congenital (1 megaureter, ectopic ureter, retrocaval) • Inflammatory (TB, Crohn, PID, etc) • Intraluminal (stone, clot, tumor, stricture)
Congenital UPJ obstruction • #1 cause of renal mass in newborn • Associations • Ipsilateral reflux • Lower moiety of duplication • Most common cause of obstruction with horseshoe kidney • Causes • Stricture, disordered peristalsis, ischemia, redundant urothelium, crossing vessel, etc.
Congenital UPJ obstruction • Imaging: • Mass in plain films • US – dilated pelvo-calyceal system (communicating cysts): dilatation-fluid equal to cortical thickness • NM – obstructive pattern w/o lasix response • Pitfalls • US may underestimate hydro due to oliguria/dehydration in newborn • MCDK may look like UPJ if only a couple cysts present
Congenital UPJ obstruction • Work-up • VCUG: co-existant ipsilateral reflux*, urethral obstruction, contralateral reflux • Scintigraphy: site of obstruction & renal function • *obstruction to reflux at UPJ, dilution of contrast in dilated renal pelvis, delay in drainage from renal pelvis
Multicystic Dysplastic KidneyBean or Ball • Not a true “cystic disease” • etiology is severe embryonic obstruction during metanephric stage of development • So…it’s an obstruction • Hallmark: non-function of the kidney • Bilaterality not compatible with life due to severe pulmonary hypoplasia
Multicystic Dysplastic Kidney • 2nd most common renal mass in newborn • Types • Pelvoinfundibular – atresias at ureter, pelvis, infundibulae • Most common, grape-like collection of cysts and dysplastic glomeruli, atrophied tubules • Hydronephrotic-atresia of proximal ureter alone • Uncommon (5%)
Multicystic Dysplastic Kidney • Imaging • US - Isolated cysts without a definable pelvis and without normal renal tissue • IVP – lack of function • NM – absence of perfusion & lack of function (may have minimal activity 24-48hrs)
Multicystic Dysplastic Kidney • Work-up • US: frequent contralateral UPJ, reflux, • VCUG: opposite reflux/obstruction • MAG3, DTPA renogram • Management • Usually observation (natural history of involution) • Nephrectomy for GI obstruction/respiratory compromise, hypertension • ?malignancy probably not increased over baseline
Solid Renal MassesBeans and Balls! • Hematoma • Abscess • Tumor
R/P mass in Neonate • Renal • Hydronephrosis • Multicystic dysplastic kidney • Solid • Wilms tumor? • Perinephric hematoma? • Mesoblastic nephroma? • Lymphoma? • Adrenal • Hemorrhage • neuroblastoma
Mesoblastic Nephroma(Fetal renal hamartoma) • Most common neonatal renal neoplasm • Present as an asymptomatic mass • Not Wilms tumor Characteristics • Benign appearing spindle cells with dysplastic nephrons • Large (8-30cm), arise in medulla • Blends with normal parenchyma • May penetrate capsule and invade locally • Rare hypercellular forms may metastasize
Mesoblastic Nephroma(Fetal renal hamartoma) • Imaging • Non-calcified abdominal mass • Look like uterine leiomyoma by US • CT vascular and entrapped collecting system excretes contrast
Mesoblastic Nephroma(Fetal renal hamartoma) • Management • Nephrectomy • No chemo or radiation (usually no mets) • Cellular form • Age >3months at surgery are more likely to need chemo/radiation
Childhood Renal Tumors • Wilms tumor & nephroblastomatosis • Renal lymphoma/leukemia • Renal cell carcinoma • Multilocular cystic nephroma • Clear cell sarcoma • Rhabdoid tumor • Angiomyolipoma (and tuberous sclerosis)
Wilms Tumor • Most common solid abdominal mass in childhood • Most common renal malignancy in child • 8% of all childhood cancer
Wilms Tumor • Demographics • Male=female • 1% familial • 7.8 per 1,000,000 children • Peaks between 2.5 to 3 years • 80% occur between 1-5 years • Presentation • Asymptomatic mass most common • Other: pain, hematuria, hypertension, fever
Wilms Tumor • Associated conditions • 8% have overgrowth disorders, genital anomalies, aniridia • Drash, Beckwith-Wiedemann, Soto, NF, KTW, Bloom, WAGR, 45X, etc • 5% bilateral & higher incidence of above • These children’s siblings have a 30% chance of development of Wilms • Nephroblastomatosis (Wilms precursor)
Wilms Tumor • Nephroblastoma (Wilms “in situ”) • Rests of metanephric blastema persisting after 34-36 weeks gestational age • Present in most cases of bilateral Wilms, 15% unilateral disease • Intralobular NR • Younger age • Drash & sporadic aniridia • Metachronous Wilms • Perilobular NR • BWS, Tr18, hemihypertrophy • Synchronous Wilms
Wilms Tumor • Nephroblastomatosis • ImagingAppearance • Nodules • Subcapsular hypodense plaques • US – iso, hypo, hyperechoic (relatively insensitive) • CT w contrast better for surveillance • MRI ? Able to distinguish Wilms from nephroblastomatosis
NR Plaque-like Ovoid Lenticular Homogeneous on all sequences Hypotense post gad Wilms Round/spherical Heterogeneous pre gad Heterogeneous post contrast NR versus Wilms at MRI
Nephroblastomatosis • Treatment • Confluent disease treated with chemotherapy
Wilms Tumor • Pathology • Solid, necrosis, hemorrhage, 15% calcifications • Capsule usually intact • Invades nodes, veins, rarely urothelium • Decreasing 10’s • 10% renal vein invasion • 10% IVC extension • 10% right atrial extension
Wilms Tumor • Pathology • 5% bilateral • 7% unilateral and multicentric • Metachronous cases may occur up to 10 years later • 10% unfavorable histology
Wilms Tumor • Pathology • Lung mets up to 20% at diagnosis • Liver mets 10% of patients • Bone mets rare (lytic) • Bilateral tumors may have different grades of histology (favorable vs unfavorable)
Wilms Tumor • Staging • I – limited to kidney, completely resected • II- outside kidney, completely resected • III – confined to abdomen • IV – hematogenous mets • V – bilateral initial/during treatment
Wilms Tumor - Radiology • Nitwits (NWTS) don’t agree on optimal imaging – nonsense like IVP’s persist • IVP – distortion of collecting system, non-function (vascular compression) • US – • CDS excellent for venous tumor thrombi in IVC • Echotexture similar to liver • Sharply marginated