Editing Pediatrics: Renal and Adrenal Oncology (section)

=== Diagnosis and Evaluation ===

==== History and Physical Exam ====
* '''Classically presents with a palpable mass or gross hematuria but abdominal pain and hypertension can also be present'''
** '''<span style="color:#ff0000">> 90% have an asymptomatic abdominal mass discovered incidentally</span>''' by a family member or physician
*** '''Abdominal mass may be firm, non-tender and classically does not cross the midline (neuroblastoma can cross midline)'''
*** '''Other symptoms include fever, anorexia, and weight loss in 10% of patients'''
*** Rarely, children may have acute abdominal pain from tumor rupture into the peritoneal cavity or bleeding within the tumour.
** '''<span style="color:#ff0000">≈20% have hematuria at diagnosis'''
*** '''Gross hematuria warrants further evaluation to rule out tumor extension into the collecting system'''
** '''<span style="color:#ff0000">≈25% have hypertension at diagnosis'''
*** Hypertension can be caused by elevated plasma renin levels
* Compression or invasion of adjacent structures may result in an atypical presentation. A persistent varicocele in the supine position or hepatomegaly may be reflective of inferior vena cava obstruction from tumor thrombus
*Aniridia
**
** Found in 1% of Wilms tumor patients
** Caused by an abnormality of the PAX6 gene located adjacent to the WT1 gene
*** A deletion of chromosome 11 has been found most frequently in Wilms tumor patients with aniridia
*'''The development of a renal tumor in a child known to have aniridia, hemihypertrophy, or other syndromes associated with an increased incidence of nephroblastoma is most likely to be a Wilms tumor.'''
*'''Genitourinary anomalies (renal fusion anomalies, cryptorchidism, hypospadias) are present in 4.5% of patients with Wilms tumor'''
** '''May be associated with horseshoe kidney'''
** '''Increased risk of Müllerian duct anomalies in girls with Wilms tumor'''

==== Labs ====
* '''<span style="color:#ff0000">Preoperative laboratory evaluation of a child with an abdominal mass should include''' 
*#'''<span style="color:#ff0000">CBC'''
*#'''<span style="color:#ff0000">Liver enzymes'''
*#'''<span style="color:#ff0000">Serum electrolytes, including calcium'''
*#'''<span style="color:#ff0000">Renal function assessment (blood urea nitrogen, creatinine)'''
*#'''<span style="color:#ff0000">Urinalysis'''
* '''<span style="color:#ff0000">As many as 8% of newly diagnosed patients with Wilms tumor will have acquired von Willebrand disease, coagulation panel should be considered'''

==== Imaging ====
* '''<span style="color:#ff0000">Regional'''
** '''<span style="color:#ff0000">Abdominal ultrasound''' 
***'''<span style="color:#ff0000">For all patients with a suspected renal mass, evaluation should begin with an abdominal ultrasound to confirm a solid renal mass and preliminarily evaluate the contralateral kidney.''' 
****This approach guides subsequent imaging specific to the primary renal tumor
** '''<span style="color:#ff0000">CT or MRI abdomen/pelvis with IV contrast'''
***'''<span style="color:#ff0000">All patients with suspected Wilms tumour should undergo either CT or MRI of the abdomen/pelvis''' with IV contrast
**** '''See [https://radiopaedia.org/articles/wilms-tumour Figures]'''
**** '''MRI avoids radiation but typically requires anesthesia or sedation in young children.'''
**** A precise histologic diagnosis cannot be obtained on the preoperative imaging studies
**** The renal origin of the mass is usually apparent on CT, but it can be mistaken for neuroblastoma.
**** Bilateral or multicentric tumors are more typical of Wilms tumor, but renal lymphoma can manifest in this fashion.
** '''IVC involvement'''
*** Occurs in 4% of Wilms tumor patients
***Doppler ultrasonography is particularly helpful to exclude intracaval tumor extension
*** MRI can reliably identify extension of tumor into the IVC.
*** CT was able to detect all clinically significant IVC tumor extension when compared with ultrasonography
** '''<span style="color:#ff0000">Determination of inoperability must be made at surgical exploration, not based on imaging.'''
* '''<span style="color:#ff0000">Distant metastases'''
** '''<span style="color:#ff0000">Chest CT'''
*** '''Lung is the most common site of distant metastasis'''

==== Other ====
* '''Pre-operative tumor biopsy'''
** '''<span style="color:#ff0000">Rarely indicated and has serious treatment implications due to concern for tumor spillage and risk of local recurrence'''
* '''Ureteral involvement'''
** Ureteral tumor extension has been reported in 2-5% of patients with WT
** '''Any patient with a renal mass and gross hematuria should undergo cystoscopy with a retrograde pyelogram at the time of nephrectomy to determine if ureteral extension is present.'''
*** Complete resection of tumor en bloc is important in the management of these cases, as determining the distal extent of ureteral involvement can ensure complete resection