The first, a 2-month-old girl with stage I WT, was admitted for respiratory insufficiency secondary to abdominal tumor mass with chyloperitonitis requiring tumor nephrectomy, with a PICU course complicated by postoperative chyloperitonitis, hypertension, acute kidney injury, syndrome of inappropriate ADH secretion (SIADH), Klebsiella pyelonephritis, and invasive candidiasis. Here, AVP is linked to neoplasm.