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Multicystic Dysplastic Kidney (MCDK)

Definition of Multicystic Dysplastic Kidney (MCDK)

Multicystic dysplastic kidney (MCDK) is a severe form of congenital kidney malformation characterized by renal noncommunicating cysts and the absence of a normal pyeloureteral system (Hains et al., 2009).

Epidemiology

The incidence is 1:4300 live births. Multicystic renal dysplasia is the most common abdominal tumor in the neonatal period and the most common cystic lesion of the kidney in childhood.

Etiology

The etiology is unclear, there are several theories explaining a multicystic dysplastic kidney:

• Fetal ureteral atresia
• Abnormal induction of the metanephritic blastema by the ureteral bud.
• Viral infections

Most cases of multicystic renal dysplasia are subject to spontaneous involution.

Signs and Symptoms of Multicystic Renal Dysplasia

• Abdominal tumors in Newborns and children.
• Later, spontaneous involution is typical and may lead to the misdiagnosis of renal agenesia.
• Associated malformations of the genitourinary tract: contralateral UPJ obstruction in 3–12%, contralateral vesicoureteral reflux in 5–20%, benign cystic dysplasia of the testis
• Fatal Potter syndrome in bilateral disease possible

Diagnostic Workup in MCDK

• Ultrasound of the kidneys: cystic tumor in the renal fossa. Regular examinations are necessary due to the slightly increased risk of Wilms tumor.
• Voiding Cystourethrogram: for differential diagnosis and the exclusion of contralateral vesicoureteral reflux.
• Renal scintigraphy: absent renal function on the affected side.

Treatment of Multicystic Renal Dysplasia

Perform ultrasound imaging, blood pressure test, and creatinine every 6–12 months until the age of 8 years or until involution of multicystic renal dysplasia. Perform nephrectomy if the kidney is causing symptoms (flank pain, infections, hypertension) or if the mass is suspicious for malignancy.

References

  Deutsche Version: Multizystische Nierendysplasie