Editing Pediatrics: Renal and Adrenal Oncology (section)

== Other renal tumors ==

=== Clear Cell Sarcoma of the Kidney ===
* Unlike Wilms tumor, clear cell sarcoma of the kidney is '''associated with bone and brain metastases.'''
* Bilateral involvement has not been reported, nor has the presence of Wilms tumor–associated congenital anomalies such as aniridia or hemihypertrophy.

=== Rhabdoid Tumor of the Kidney ===
* '''Most aggressive and lethal childhood renal tumor'''

=== Congenital Mesoblastic Nephroma ===

==== Epidemiology ====
*'''<span style="color:#ff0000">Most common renal tumor in infants'''
** Most common renal tumor diagnosed on pre-natal US
** Most common tumor in infants > 4 months of age
* '''Mean age at diagnosis of 3.5 months (in contrast, the median age for diagnosis of a Wilms' tumor is 3.5 years)'''

==== Subtypes (2) ====
# '''Classic type'''
#* Far more common
#* '''Rarely recur,''' provided surgical margins are negative
# '''Cellular variant'''
#* Consists of atypical spindle cells with frequent mitotic figures (25-30/10 hpf) and necrosis
#* Considered a variant of a '''fibrosarcoma'''
#* Associated with both '''local recurrence and widespread metastasis.'''

==== Diagnosis and Evaluation ====
*'''Imaging'''
**'''Typically infiltrative (whereas Wilms' tumors displace and compress renal architecture)'''

==== Management ====
* '''<span style="color:#ff0000">Radical nephrectomy'''
** '''Biopsy and partial nephrectomy are not recommended''' since the tumour occasionally extends into the hilum or perirenal soft tissue; complete excision is important to prevent local recurrence.

==== Follow-up ====
* Surveillance by interval 6 month abdominal US for the first 2 years is usually recommended for the classic variant and more aggressive follow-up with interval CT or MRI scans of the lungs and abdomen are recommended at 3-6 intervals for the first two years for the cellular variant
=== Renal Cell Carcinoma ===
* '''RCC is the most likely diagnosis in a child age >12 with a renal mass'''
* Staging
** Same TNM system as that used for adults
** 63% of children present with locally advanced or metastatic disease (N1 or M1)
* '''Pathology'''
** '''Most common histology seen in pediatric RCC is translocation''' (47% of cases)
*** Clear cell RCC is rare in pediatrics, unlike adults in whom clear cell RCC is the most common histology,
** '''[Campbell’s] Higher incidence of papillary RCC in children'''
*** These tumors are genetically unique in that they have chromosome translocations involving a common breakpoint in the TFE gene located at Xp11.2
** '''Another type of RCC more often seen in children is renal medullary carcinoma'''
*** Median age at presentation is 13 years
*** Found in patients with sickle cell hemoglobinopathy
* Diagnosis and Evaluation
** History and Physical Exam
*** Children tend to present with an abdominal mass or hematuria
** Imaging
*** Cannot differentiate RCC from other solid renal tumors
* '''Management'''
** '''Nephrectomy is mainstay of treatment'''
*** '''NSS should only be advocated in highly select patients when the lesion can be completely excised and the surgeon has adequate experience'''
**** Important to remember that the application of MIS and NSS to children with RCC is likely limited as children are frequently treated under the assumption of a preoperative diagnosis of WT.
** '''LN sampling is recommended at the time of nephrectomy in all cases of suspected RCC''' (regardless of preoperative imaging, tumor size, NSS, MIS) '''due to the high prevalence of nodal involvement'''
*** In adults, LN involvement is rare in smaller tumors, which is not the case in children. Almost half (47.5%) of children with T1 tumors have regional LN involvement; pathologically involved LNs were missed on preoperative imaging alone in >42% of cases

=== Angiomyolipoma (AML) ===
* '''The renal lesions of the TSC include:'''
*# '''AML'''
*# '''Simple cysts'''
*# '''Polycystic kidney disease'''
*# '''RCC'''
** '''AML develops in up to 80% of patients with TSC.''' '''Renal cysts occur in up to 30% of patients with TSC.'''
** Mutations of 1 of 2 genes on chromosome 9 (TSC1) and chromosome 16 (TSC2) are found in 85% of TSC patients
* '''Management'''
** '''Children with growing lesions can be managed with embolization or partial nephrectomy before they become symptomatic with bleeding.'''
*** '''The risk of serious bleeding appears to correlate with a diameter > 4 cm'''
** '''mTOR inhibitors have shown promise as a new type of therapy for reducing the size of TSC-associated AMLs'''

=== Metanephric Adenofibroma ===

=== Solitary Multilocular Cyst and Cystic Partially Differentiated Nephroblastoma ===
* Solitary multilocular cyst, or multilocular cystic nephroma, is an uncommon, benign renal tumor