The growing use of maternal fetal ultrasound is leading to the discovery of an increasing number of suprarenal masses. Our experience with a cystic suprarenal mass detected on antenatal ultrasound is described. Location and radiographic features could not rule out the possibility of a cystic neuroblastoma; therefore, surgical resection of the mass was performed. Despite the absence of common radiologic characteristics, the pathology of the specimen revealed a non-functioning upper pole of a duplex kidney with complete duplication of the collecting system. Neonatal evaluation and management and the differential diagnosis are discussed.Can Urol Assoc J 2010;4(4):E94-96
Case reportA routine second trimester ultrasound examination of a 28-year-old female (gravida 2, para 1) showed a well circumscribed, hypoechoic mass on the upper pole of the right fetal kidney. The mass measured about 6 cm in its largest diameter and appeared predominantly cystic in structure. The remainder of the detailed sonographic evaluation was unremarkable and no ureterectasis or ureterocele was observed. Size, echogenecity and structure of the mass remained unchanged throughout the pregnancy on repeated scans. An uneventful vaginal delivery at 38 weeks gestational age resulted in a female child with healthy Apgar scores.Postpartum examination of the neonate was completely normal, without palpable abdominal mass or lumbosacral abnormality. Abdominal ultrasound at 3 days demonstrated that the cystic structure remained unchanged in size and appeared contiguous with the upper pole of the kidney. The perinatal period was complicated with a simple, culture-positive urinary tract infection at 4 months, which was treated with oral cephalexin. The child was followed with serial ultrasounds at 3 month intervals during her first year of life (Fig. 1). Throughout this period, the cyst was noted to increase in size by a small amount (less than 1 cm in greatest diameter), but remained unchanged in echogenicity and structure. Renal size was comparable bilaterally throughout this period.At 11 months, the child was admitted to hospital with a second culture-positive urinary tract infection and treated with intravenous ampicillin and gentamicin. An ultrasound performed during her admission suggested that the cystic structure was more likely suprarenal in origin and displacing the right kidney. Subsequent imaging with a voiding cystogram was normal. A magnetic resonance imaging (MRI) scan at this time further suggested suprarenal origin of the cyst with compression and anterior displacement of the upper pole of the right kidney (Fig. 2). Neither hydroureter nor ureterocele was observed on MRI.Based on the location and radiologic appearance of the cyst, our differential diagnosis included simple renal cyst, duplex kidney and adrenal neuroblastoma. . Due to the inability to eliminate neuroblastoma from the differential diagnosis, the patient was referred to our centre for surgical resection of the mass at 15 months. Via a flank approach, we explored the ...