'Wolf in Sheep's Clothing': Third Trimester Diagnosis of Rare Adrenal Malignancy Masquerading as Common Renal Anomaly

Neuroblastoma, a rare embryonic tumour of neural crest origin, is one of the most common paediatric malignancies, accounting for 8%-10% of childhood cancers. It most often arises in the adrenal glands and can present in utero during the third trimester.

This case report presents a 29-year-old primiparous woman whose foetus was found to have bilateral adrenal masses during a routine 37-week ultrasound. The masses were initially suspected to be renal in origin, but subsequent imaging revealed bilateral adrenal involvement, leading to the diagnosis of stage 4S neuroblastoma. Postnatal ultrasound confirmed solid and cystic masses in both adrenal glands, with additional liver involvement.

This case emphasises the importance of antenatal imaging in the early detection of neuroblastoma and highlights the role of ultrasound in identifying heterogeneous, hyperechoic suprarenal masses, which can be key indicators of the condition. The diagnostic dilemma in this case relates to the masses mimicking renal lesions, highlighting the importance of detailed ultrasound imaging of foetal abnormalities. In this case, the tumour's presence was confirmed through further imaging and biochemical testing, and the baby received specialised care at a tertiary centre. Liver metastases often assist in confirming the diagnosis of stage 4S neuroblastomas, which generally have a favourable prognosis, with many cases regressing spontaneously. Early detection, particularly via prenatal imaging, significantly improves outcomes, as it allows for careful monitoring and timely intervention. The baby in this case has responded well to treatment, underscoring the importance of early diagnosis and ongoing postnatal surveillance.