Introduction:

Multicystic renal dysplasia is a congenital anomaly characterized by an afunctional kidney with cysts of different sizes. It is considered a developmental abnormality, although hereditary cases have been described. The malignant degeneration of this dysplasia has been pointed out, but its association is very rare.

Objective:

Describe a patient with Wilms tumor associated with multicystic renal dysplasia.

Case Presentation:

10-year-old female patient to whom prenatal ultrasounds did not detect urinary tract abnormalities and at age 7 an ultrasound study detected cysts in the left kidney. She did not comply with the indicated clinical and ultrasonographic follow-up and left the consultation; at 10 years old, she attended the doctor for acute respiratory symptoms and when palpating the abdomen there was a mass on the left flank of woody consistency, not painful and with lumbar contact. A renal biopsy was conducted and Wilms tumor was diagnosed; cytostatic treatment was indicated, and a nephrectomy was performed that confirmed the diagnosis. Among the family history is reported a brother who died before 72 hours of birth due to bilateral multicystic renal dysplasia and a mother with nephropathy by vesicoureteral reflux.

Conclusions:

The described patient has three rare characteristics: a malignant tumor associated with multicystic renal dysplasia, the hereditary possibility due to the sibling's history of bilateral dysplasia, and a Wilms tumor at 10 years of age, which demonstrates the importance of follow-up in these patients.