Right-sided multicystic dysplastic kidney in a 40-day-old infant associated with inguinal hernia and club foot: a case report

Introduction: Multicystic dysplastic kidney (MCDK) is a congenital, nonhereditary renal malformation characterized by multiple noncommunicating cysts separated by dysplastic stroma containing primitive ducts, cartilage, and glomeruli, with the absence of normal renal parenchyma. It results from abnormal interaction between the ureteric bud and metanephric blastema during fetal development. Most cases are unilateral and detected incidentally on prenatal or postnatal imaging, although large cystic kidneys may present with abdominal distension or respiratory distress due to mass effect. Associated anomalies, including contralateral renal or extrarenal defects, are not uncommon. Presentation of case: A 40-day-old male infant presented with progressive abdominal distension and respiratory distress. Ultrasound revealed a right kidney replaced by multiple noncommunicating cysts (88 × 72 mm) containing clear fluid, with no renal parenchyma – consistent with MCDK. The left kidney appeared normal. Additional findings included a right inguinal hernia containing bowel loops, a right-sided heart, and a club foot deformity. Voiding cystourethrography and renogram showed a nonfunctional right kidney (3%) and a left kidney with ureteropelvic junction obstruction (97%). The patient underwent right nephrectomy with simultaneous hernia repair and later correction of the left obstruction, recovering uneventfully. Clinical discussion: MCDK occurs in approximately 1 in 4000–5000 live births. It may coexist with contralateral or extrarenal anomalies, as in this case. Histopathology confirmed cystic renal dysplasia. Conclusion: This rare case of right-sided MCDK associated with inguinal hernia and club foot underscores the importance of early diagnosis, comprehensive evaluation of the contralateral kidney, and timely surgical management to ensure favorable outcomes.