PEDIATRIC RENAL TUMORS
Presenter- Dr. Bipin JosephModerator- Dr. Anto Richie
Neonate – Mesoblastic nephroma – Multicystic dysplastic kidney
6 months to 5 years of age –WILMS TUMOR – Nephroblastomatosis – Medullary tumors – Multilocular cystic nephroma
> 5 years – Renal cell cancer
WILMS TUMOR
Epidemiology 85% of renal masses 6-7% of all childhood cancers Approximately 500 cases/year Deletion of tumor suppressor
genes on short arm of chromosome
11 11p13 locus (WT1 gene) 11p15 locus (WT2 gene)
Risk Factors Aniridia
WAGR syndrome (aniridia, genital abnormalities, retardation) (WT1 gene)
Beckwith-Wiedemann syndrome (hemihypertrophy, omphalocele, macroglossia, hypoglycemia) & isolated hemihypertrophy (WT2 gene)
Drash syndrome (nephritis & male pseudohermaphrodism) (WT 1 gene)
Gross Features Large cortical mass(400 to 500
gm) Hemorrhage & necrosis(90%) Pseudocapsule Spares collecting system Calcification & fat <10%
Favorable Histology (85%) Triphasic composition – Metanephric blastema – Immature stroma – Tubular elements Good prognosis if triphasic
“Unfavorable” Histology (15%) Anaplastic changes – Nuclear enlargement »> 3x size –Hyperchromatic nuclei – Atypical mitotic figures Implies poor prognosis & resistance to conventional therapy
Wilms Tumor: Clinical Features Mean age: 36 m (range, 6 m-4
yr) Symptoms – Mass: 90% – Pain, fever, hematuria: 30% –Hypertension: 75% - 90% – Aniridia, hemihypertrophy – Budd-Chiari syndrome
Wilms Tumor: US Findings
Well-defined margins Solid, intrarenal mass Tumor matrix –Homogeneous: 50% –Heterogeneous : 50% IVC thrombus (5-10%) Relatively avascular
Wilms Tumor
Wilms Tumor
Wilms Tumor
Wilms Tumor: Venous Extension • 5-10% of cases • Tumor thrombus above IVC alters surgical approach – Cardiopulmonary bypass
Wilms Tumor: Caval Thrombus
Tumor Thrombus
Bilateral Wilms Tumor
•5-10% of patients– (synchronous disease)
Dominant renal mass & small contralateral
tumor or bilateral large masses
Alters therapy – initial chemotherapy – delayed surgery
Wilms Tumor: Treatment En bloc resection of affected
kidney Excision of nodes and lung
nodules Postop chemotherapy Preoperative chemotherapy for
invasive disease or bilateral Wilms, then
surgery For all stages 2-year survival of
90%
NEPHROBLASTOMATOSIS
Defined as "the presence of nephrogenic
rests or nephrogenic blastema beyond 36
weeks gestation” Important because it is a
precursor to Wilms tumor Patient age < 2 years
Nephrogenic Rests
Location2 types by location Perilobar – Peripheral cortex or columns of Bertin Intralobar – Deep cortex – Greater risk ofWilms tumor (4-
5%)
Nephrogenic Rests
Nephroblastomatosis: Imaging
Two basic appearances: –Confluent peripheral tumor –Focal peripheral cortical mass
USG: hypoechoic
Diffuse Nephroblastomatosis
Focal Nephroblastomatosis:Discrete Cortical Nodules
Nephroblastomatosis: Treatment
Controversial Chemotherapy in some centers Close imaging surveillance
forenlarging masses in others Renal sparing surgery
MESOBLASTIC NEPHROMA
5% of all renal tumors Tumor of the neonate – mean age, 2 months(first 6
m) Incidental mass May be diagnosed in utero - polyhydramnios
Clinically palpable flank mass Hypertension hematuria hypercalcemia
Mesoblastic Nephroma: Path
Gross Cortical tumor Unencapsulated Hemorrhage & necrosis uncommon Histology – mature spindle cells
Mesoblastic Nephroma: Imaging
Usually homogeneous cystic changes rare Well circumscribed Looks like Wilms but age is the clue
Mesoblastic Nephroma
Mesoblastic Nephroma:Therapy and Prognosis
Most behave in benign fashion Cured by nephrectomy Metastases & recurrence very
rare –Associated with atypical
cellular histology Overall prognosis excellent
TUMORS OF MEDULLARY ORIGIN 6% of renal neoplasms
Rhabdoid tumor Clear cell sarcoma
Malignant rhabdoid tumor
– infants – associated with CNS tumors
(PNET) Large masses Infiltrating margins
Rhabdoid Tumor:
Heterogeneous mass Peripheral low density crescent Ill-defined margins
Rhabdoid tumor – Poor prognosis – 80% have metastases at
diagnosis »lung, liver, brain, nodes –20% survival @ 18 months
Clear cell sarcoma
– 1st 4 years of life – bone metastases (60-70%) Infiltrative aggressive tumors
Clear Cell Sarcoma
Heterogeneous mass Cystic changes (70%) Ill-defined margins Bone metastases
Clear cell sarcoma –Survival rates 60%-70%
Cystic Masses
< 5 years of age – Multilocular cystic renal tumor – Multicystic dysplastic kidney
> 5 years of age –Simple renal cysts (rare)
MULTILOCULAR CYSTIC RENAL TUMORThe term “multilocular cystic renal tumor”encompasses two histologically distinct
cystictumors: 1. cystic nephromas composed of epithelial
lined cysts separated by fibrous septa with mature tubules
2. cystic partially differentiated nephroblastomas composed of cysts with septa containing foci of blastemal cells.
Multilocular Cystic Renal Tumor:
Clinical Findings Biphasic age distribution – Boys 3 months to 2 years – Women > 40 years Usually asymptomatic mass Pain & hematuria from ureteral
prolapse of cyst
Multilocular Cystic Renal Tumor
Composed of cysts & septa Encapsulated Mean diameter 7 to 10 cm
Multilocular Cystic Renal Tumors
Cystic, fluid-filled mass Varying thickness septations Avascular, except septa
Multilocular Cystic Renal Tumor
Multilocular Cystic Renal Tumor:Differential Diagnosis Multicystic dysplastic kidney – Non-functioning – Entire kidney involved – Conservative treatment, not
surgery Found in neonates (day 1) Typically involutes
MCDK: Gross Pathology & Imaging
Cysts of varying sizes Randomly arranged Non-communicating No normal parenchyma Associated atresia of ureter or pelvis
ANGIOMYOLIPOMA Fat-containing Masses Any age, but more often after 5 years Associated with tuberous sclerosis 80% of tuberous sclerosis patients
have angiomyolipomas also are associated (although to a
lesser extent) with von Hippel-Lindau syndrome and neurofibromatosis.
Angiomyolipoma: USG
Angiomyolipoma: CT
Because of the increased risk of hemorrhage with large angiomyolipomas, the current recommendation is to treat an angiomyolipoma
greater than 4 cm with surgical resection or selective catheter embolization. In
Thus, ultrasound surveillance is currently recommended every 2–3 years before puberty and yearly thereafter to detect any increase in the size of the mass.
OSSIFYING RENAL TUMOR OF INFANCY Ossifying renal tumor of infancy is an
extremely rare lesion found in infants as young as 6days to 14 months.
The tumor consists of an osteoid core, osteoblast, and spindle cells
usually presents as an abdominal mass that may be accompanied by hematuria
On ultrasound, ossifying renal tumor of infancy presents as a heterogeneously echogenic intrarenal mass with posterior acoustic shadowing due to the calcified components of the tumor
OSSIFYING RENAL TUMOR OF INFANCY
TUMORS OF OLDER CHILDREN-- RENAL CELL CANCER Peak incidence: 15-19 yr
Clinical findings pain, hematuria, mass
Imaging findings: solid renal mass same as adult
RENAL CELL CARCINOMA (RCC) Is extremely rare in children. It
usually occurs in periadolescent children but may develop in younger children with von Hippel-Lindau syndrome
in children who have undergone prior chemotherapy for other renal tumors
Painless hematuria, flank pain, or a palpable mass are the usual presenting symptoms of RCC.
Most common metastatic diseases Neuroblastoma Leukemia Lymphoma
NEUROBLASTOMA
arise from primitive neuroblasts in the neural crest of sympathetic ganglia.
malignancy; 80% of cases occur in children under 5 years old.
Neuroblastoma most frequently presents as an abdominal mass, with two thirds of children having metastatic disease at the
time of presentation.
Neuroblastoma often displaces the ipsilateral kidney,
although it can involve the kidney by direct extension and may encase the renal arteries or ureters to cause hypertension or hydronephrosis
These hematogenous metastases appear as well-circumscribed hyperechoic renal lesions on ultrasound and hypoenhancing masses on contrastenhanced CT
Wilms' tumor vs Neuroblastoma Wilms'
<10% are calcified; more often a curvilinear pattern
Occasional local para-aortic adenopathy (less common than with neuroblastoma)
IVC invasion has high positive predictive value
Mets to lungs common
Neuroblastoma Often calcified; scattered
pattern throughout mass Large regional adenopathy High predictive value:
encasement of great vessels, spinal canal invasion, paravertebral mass
Moderate predictive value: extension across midline, displacement of great vessels
Mets to liver, bone common Elevated urine
catecholamines
LEUKEMIA
Leukemic involvement of the kidneys occurs most often from acute lymphoblastic leukemia- the most common childhood malignancy.
Both ultrasound and CT in kidneys with leukemic infiltration show diffuse bilateral renal enlargement with loss of the normal corticomedullarydifferentiation The affected renal cortex is relatively hypoenhancing on contrast enhanced CT
LYMPHOMA
Lymphomatous involvement of the kidneys usually occurs by direct extension of retroperitoneal lymphoma or by hematogenous spread, most often from non-Hodgkin lymphoma
Lymphoma of the kidneys can be difficult to detect on ultrasound.
On CT, renal lymphomatous lesions are hypoenhancing compared with the adjacent normal renal parenchyma
Summary:Neonate Mesoblastic nephroma Multicystic dysplastic kidney
6 months to 5 years of age WILMS TUMOR Nephroblastomatosis Medullary tumors Multilocular cystic nephroma
> 5 years Renal cell cancer
Infants & Young Children:Which Solid Renal Tumor?
Homogeneous solid mass? Wilms, mesoblastic nephroma Subcapsular or peripheral solid tumor? Nephroblastomatosis Large cystic areas or bone mets? Clear cell Peripheral fluid/cystic collection? Rhabdoid Infiltrative margins? Rhabdoid/clear cell sarcoma Well circumscribed margins? Wilms, mesoblastic nephroma
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