Incidental Postnatal Diagnosis of Unilateral Right Multicystic Dysplastic Kidney in an Asymptomatic Neonate: A Case Report.

Abstract

Background:
Multicystic dysplastic kidney (MCDK) is a common congenital anomaly of the kidney and urinary tract characterized by replacement of normal renal parenchyma with multiple non-communicating cysts due to abnormal embryologic development. The condition is usually detected during routine antenatal ultrasonography and is frequently asymptomatic after birth. Recognition of incidentally diagnosed unilateral MCDK is important because current management emphasizes conservative follow-up rather than surgical intervention in the absence of complications.
Case Report:
A full-term neonate presented with excessive crying since birth without fever, vomiting, poor feeding, urinary symptoms, or antenatal imaging records. Physical examination and laboratory investigations, including renal function tests and urinalysis, were unremarkable. Abdominal ultrasonography performed to exclude an intra-abdominal cause revealed an enlarged right kidney measuring 5.39 × 3.39 cm, almost completely replaced by multiple non-communicating cysts of varying sizes with marked absence of normal renal parenchyma and no identifiable pelvicalyceal system, consistent with multicystic dysplastic kidney. The left kidney demonstrated normal size, morphology, corticomedullary differentiation, and echogenicity without hydronephrosis or focal lesions. A diagnosis of isolated unilateral right MCDK was established. As renal function was preserved and the contralateral kidney was normal, conservative management with parental counseling, serial ultrasonographic surveillance, blood pressure monitoring, and periodic renal function assessment was recommended. At early follow-up, the infant remained asymptomatic with appropriate growth and no episodes of urinary tract infection.
Conclusion:
This case highlights the incidental postnatal diagnosis of unilateral multicystic dysplastic kidney during evaluation for an unrelated neonatal complaint. Ultrasonography remains the diagnostic modality of choice because of its characteristic imaging features and ability to assess the contralateral kidney. Recognition of isolated unilateral MCDK facilitates appropriate counseling, avoids unnecessary surgical intervention, and supports long-term conservative surveillance to preserve renal health.