Congenital mesoblastic nephroma with distant metastasis in a premature twin gestation

Congenital mesoblastic nephroma (CMN) is a rare renal tumor of infancy. Here, we present a case of CMN presenting in a 29 week premature male in a twin gestation. An abdominal mass had been noted on prenatal ultrasound. He was initially treated with right radical nephrectomy. Pathology was consistent with cellular type CMN. Three months postoperatively, the patient developed pulmonary metastasis and underwent wedge resection of the right lung lesion. He subsequently underwent adjuvant chemotherapy, to which he has responded well. We discuss the presentation and management of patients with CMN and address the indications for postoperative chemotherapy.