Introduction: Abdominal masses in the neonatal period often present a diagnostic challenge. The aim of this study
was to evaluate which urological pathologies cause the formation of a neonatal mass, the diagnostic pathway and
surgical outcome.
Patients and methods: The medical and radiological records of 30 neonates who were admitted to the Neonatal
Surgical Unit of Yorkhill Sick Children Hospital, Glasgow with an abdominal mass over a five-year period
(2008-2013) were reviewed. Data collected included demographics, gestational age, radiological investigations,
operative findings and complications.
Result: Seventeen neonates (9 males, 8 females) were identified with an abdominal mass arising from the urological
tract. Four boys were found to have posterior urethral valves while in 4 girls a duplex kidney with a ureterocele was
identified. In the remaining 9 patients the palpable mass was caused by: vesicoureteric reflux (n=2), multicystic
dysplastic kidney (n=2), polycistic kidney disease (n=1), ectopic kidney (n=1), pelvi-ureteric junction obstruction
(PUJO) (n=1), unilocular renal cyst (n=1), PUJO and vesicoureteric junction obstruction (n=1). Nine patients
required a form of urinary diversion and in two of these patients a nephrostomy was followed by a pyeloplasty, 2
required incision of ureteroceles, 1 nephrectomy, 1 partial nephrectomy, 1 STING and 1 primary valve ablation.
Conclusion: Only 70% of newborns with abdominal masses were diagnosed antenatally, while 30% were detected
postnatally. Posterior urethral valves remain the most common cause of a neonatal mass in a male, while duplex
kidneys with ureterocele were seen in girls. Half of the patients will require a form of urinary diversion in the
neonatal period. The large majority (88%) of abdominal masses of urological origin required surgical intervention.
Lower abdominal mass in a 16-year old adolescent: an unusual presentation of posterior urethral valves
