Sandbox: DDx Kidney mass

1-2 yo patients Constitutional symptoms May have abdominal pain, constipation, proptosis, periorbital ecchymoses, back pain, weakness, hypertension, and subcutaneous nodules Opsoclonus myoclonus ataxia syndrome

Heterogeneous mass on U/S Internal vascularity Necrosis Calcification

Nonmalignant causes

anaplastic sarcoma clear cell sarcoma mesoblastic nephroma metanephric stromal tumor nephroblastomatosis / nephrogenic rests neuroblastoma oncocytoid carcinoma after neuroblastoma ossifying tumor renal cell carcinoma rhabdoid tumor translocation carcinoma (children)