Differential

• < 6 mo: congenital mesoblastic nephroma (CMN)
• CMN median age 2.4 mo; uncommon to be metastatic/(considered benign/surgery usually curative)
• Rhabdoid tumor
• Consider Wilms but more rare in infancy
• < 12 yrs: Wilms tumor (mean age 3.5 yo, most before 5y)
• Multilocular cystic nephroma ~ 2y, usually cured with excision. Genetic counseling for DICER mutation
• Clear cell sarcoma of the kidney median 3y
• Rhabdoid tumor of the kidney ~ 18 mo, Majority stage III-IV
• > 12 yrs: renal cell carcinoma
• Most commonly translocation related
• Renal medullary carcinoma a/w sickle cell
• Metanephric adenoma
• Cystic vs solid vs fat containing
• Incidental vs symptomatic

• PMH/FH: sydnromic conditions, sickle cell
• CBC, CMP, coags (2% of Wilms have acquired von Willebrand deficiency)

• Abdominal US to start
• If there is a mass - CT/MRI of abdomen/pelvis