RESUMO
Paraneoplastic syndromes are rare disorders that are triggered by an altered immune system response to neoplasm. Paraneoplastic syndromes may be the first or the most prominent manifestations of cancer. Wilm's tumor is the most frequent pediatric renal malignancy and usually presents with abdominal mass. Unusual presentations like acquired von Willebrand disease, sudden death due to pulmonary embolism and Cushing syndrome have been described in the literature. Cushing syndrome, as the presenting symptom of a malignant renal tumor in children, is a very rare entity. Few case reports are available in the literature exploring the option of preoperative chemotherapy as well as upfront nephrectomy. We report a rare case of paraneoplastic Cushing syndrome due to a Wilm's tumor. Based on gradual decrease of postoperative weight, blood pressure, serum adrenocorticotropic hormone, and plasma cortisol levels, along with histological confirmation of Wilm's tumor, paraneoplastic Cushing syndrome due to Wilm's tumor was confirmed