Cushing syndrome secondary to CRH-producing Wilms tumor in a 6 year old

Cushing syndrome is caused by prolonged exposure to elevated serum cortisol. It is uncommon in children, and etiology includes pituitary adenoma, adrenal tumor, and exogenous glucocorticoid administration. Rarely, it is paraneoplastic in origin. We present a case of paraneoplastic Cushing syndrome due to Wilms tumor that secreted corticotropin-releasing hormone (CRH). A 6-year-old male presented with polyphagia and weight gain. He showed Cushingoid appearance, hypertension, and palpable left flank mass. Serum cortisol and adrenocorticotropic hormone (ACTH) levels were elevated. Computed tomography showed a neoplasm originating from the left kidney. Pathologic diagnosis of Wilms tumor was made upon nephroureterectomy. Immunohistochemical staining was positive for CRH and negative for ACTH. All features of Cushing syndrome disappeared after surgery. This represents a rare case of Cushing syndrome secondary to Wilms tumor in which CRH production has been demonstrated.