Wilms Flashcards
What proportion of patients with a Wilms’ tumor has a concurrent congenital abnormality?
10%
Most common:
WAGR - WT, Aniridia, Genitourinary malformation, mental Retardation
Beckwith-Wiedemann - Visceromegaly, macroglossia, omphalocele and hyperinsulinemic hypoglycemia, at risk of WT and hepatoblastoma
Denys-Drash syndrome - nephropathy, renal failure, male pseudohermaphroditism and WT
What are the imaging findings that are consistent with a Wilms’ tumor?
“Claw sign” - kidney appears to be grabbing the tumor
Tumor displaces rather than encases adjacent structures
What proportion of renal tumors in children are Wilms’ tumors?
91%
What are the three most common congenital syndromes that are associated with Wilms’ tumors?
WAGR - WT, Aniridia, Genitourinary malformation, mental Retardation
Beckwith-Wiedemann - Visceromegaly, macroglossia, omphalocele and hyperinsulinemic hypoglycemia, at risk of WT and hepatoblastoma
Denys-Drash syndrome - nephropathy, renal failure, male pseudohermaphroditism and WT
If a Wilms’ tumor is significantly invading the colon, liver or other intra-abdominal organs, should the patient undergo an en-bloc resection or should they undergo neoadjuvant chemotherapy?
Neoadjuvant chemotherapy as doing a concurrent resection increases operative morbidity and mortality.
What is the first thing to check upon seeing a Wilms’ tumor on imaging?
Check the other kidney for presence of bilateral tumors
Which patients (according to COG) should undergo a biopsy first rather than undergoing a primary resection?
Tumor that impairs child’s respiratory status
Only one kidney/only one functioning kidney
If the tumor extends beyond the infrahepatic IVC
If a major liver or bowel resection would be required
If the tumor is so large (>13-15cm) that the risk of rupture precludes the possibility of doing a safe primary resection
What are the two types of histology seen in Wilms’ tumors?
Favorable histology (90%) Unfavorable/anaplastic histology
What are the three histologic elements commonly seen in Wilms’ tumors?
Blastemal cell types
Stromal cell types
Epithelial cell types
Most are triphasic (all three cell types present) but an also be biphasic or monophasic. Monophasic can make Wilms’ tumors very difficult to differentiate from other renal tumors.
Of the three histologic elements seen in Wilms’ tumors, which was shown in SIOP-9 to be extensively ablated by chemotherapy?
Blastemal elements. However, if blastemal elements persist after chemotherapy, the tumors are highly aggressive.
What is a nephrogenic rest?
Area of metanephric (embryonal tissue) persisting after the 36th week of life. It is considered a precursor lesion to WT, although only a small number transform.
If a resected specimen demonstrates both Wilms’ tumor and nephrogenic rests, what is the patient at risk for?
Metachronous WT in the contralateral kidney. Risk is particularly high in children <1y.
If a 6mo child has a WT resected and it also contains nephrogenic rests, what is required for screening?
Very close US screening for metachronous tumor in the remaining kidney, as the risk in a child <1y with nephrogenic rests is very high.
COG stage I
Tumor limited to kidney without penetration of the renal capsule or involvement of the renal sinus vessels, completely resected without rupture
COG stage II
Tumor extends beyond kidney but completely resected without tumor beyond the edges of resection, no rupture. There can be penetration of the renal capsule or invasion of the renal sinus vessels.
