Prenatal Diagnosis of Adrenal Neuroblastoma – Differential Diagnosis of Suprarenal Masses in the Third Trimester of Pregnancy

Introduction

Neuroblastoma is the most common malignant extracranial solid tumor in infancy with an incidence rate of 58 per million infants younger than one year old. It originates from the neural crest during fetal development and may arise from the sympathetic ganglia or the adrenal medulla (Gurney JG, et al. J Pediatr Hematol Oncol. 1997; 19: 428).

Prenatal detection of neuroblastoma was first described in 1983 (Fenart D, et al. Journalde Radiologie 1983; 64: 359). In the majority of antenatally diagnosed cases, neuroblastomas are adrenal in origin and right-sided. Differentiating neuroblastomas from other fetal suprarenal masses such as extralobar pulmonary sequestration, congenital adrenal hyperplasia, renal duplication, urinoma, gastric duplication cyst, and splenic cyst may be very difficult. However, improvements in ultrasound technology have made early detection possible and, combined with fetal MRI, facilitate differential diagnosis. Finally, prenatal diagnosis of a neuroblastoma is associated with a better prognosis, as it can resolve spontaneously either in utero or shortly after birth (Maki E, et al. J Ultrasound Med 2014; 33:895–904).

This is a case of a mixed cystic and solid suprarenal tumor that was identified during a routine antenatal visit in the third trimester of pregnancy and was diagnosed as an adrenal neuroblastoma.

Case description

A 27-year-old pregnant woman presented to the outpatient clinic of Alexandra Maternity Hospital in Athens, Greece during the third trimester of her pregnancy. The woman was Gravida 2 Para 0 (G2P0). The gestational age of the pregnancy was 38 weeks and 2 days. The woman’s past medical history was uneventful.

During her pregnancy, she underwent prenatal testing including first trimester scan, anomaly scan, 3^rd trimester Doppler scan without any abnormal findings. During the initial ultrasound scan we detected one fetus in occiput anterior position. All growth parameters (biparietal diameter, head circumference, abdominal circumference, femur length, estimated fetal weight) and the amniotic fluid index were within normal range for the gestational age. During the scan a well circumscribed mass was detected over the left kidney ([Fig. 1]). The mass appeared to have both cystic and solid areas and appeared to originate from the left adrenal gland ([Fig. 1]). The anatomy of the left kidney was not altered. The mass measured 4.40 × 4.12 cm ([Fig. 2]). Doppler evaluation did not reveal increased blood flow towards the mass nor a single feeding vessel ([Fig. 3]). The right kidney and right adrenal gland appeared normal ([Fig. 4a] and b). Extensive ultrasound examination of the fetus revealed no other abnormalities. After careful evaluation of the ultrasound appearance of the tumor, the diagnosis of adrenal neuroblastoma was suggested.

Fig. 1 The mass is well circumscribed with both cystic and solid areas and appears to originate from the left adrenal gland.

Fig. 2 The mass measured 4.4 × 4.12 cm at 38 weeks and 2 days of pregnancy.

Fig. 3 Doppler evaluation did not reveal increased blood flow towards the mass or a single feeding vessel.

Fig. 4 The right kidney and right adrenal gland appear normal.

With regards to the gestational age of the pregnancy, induction of labor was scheduled at 39⁺¹ weeks, resulting in the birth of a male neonate with APGAR score 9 in the first minute. Transabdominal ultrasound examination corroborated the diagnosis. The neonate was transported to the pediatric oncology department where it underwent abdominal CT scan (computed tomography scan), serum NSE (neuron specific enolase) and urine VMA (vanillylmandelic acid) and HVA (homovanillic acid) tests. The CT scan, in accordance with the prenatal ultrasound findings, revealed a well circumscribed mass above the left kidney ([Fig. 5]). NSE was 65.3 mg/l (normal value<12.5 mg/l), urine VMA was 63.2mg/g creatinine (cr) (normal value < 27 mg/g cr) and urine HVA was 47.3 mg/g cr (normal value < 35.0 mg/g cr) (LaBrosse EH et al. Cancer Res. 1980; 40: 1995–2001). The CT scan and elevated serum and urine markers confirmed the diagnosis of neuroblastoma. A strategy of observation with close follow-up visits was adopted, as prenatally diagnosed localized neuroblastomas (stage I) often regress spontaneously (Nuchtern JG et al. Ann Surg. 2012; 256: 573.).

Fig. 5 Abdominal CT scan confirmed the diagnosis of neuroblastoma of the left adrenal gland.