Outcomes of Congenital Neuroblastoma With Placental Metastases: A Systematic Review

Very little is known about congenital neuroblastoma with placental metastases. We reviewed the literature to summarise outcomes and potential risk factors for placental involvement. We performed a systematic review of the PubMed/Ovid/Medline/Embase/Cochrane databases from 1946 to 2024. The initial search identified 61 articles; 16 articles were included in the final analysis. Nineteen cases were identified (9 male, 10 female); 16 were stillborn or dead in the neonatal period. There was an adrenal primary in 89.5%, and these were detected on antenatal ultrasound in 26% of cases. Macroscopic appearance of the placenta was enlarged and hydropic in all cases. There were no significant maternal comorbidities, and no documented chromosomal abnormalities. Only two patients underwent surgery, both are well and alive at 1 year of life. Our study shows that neuroblastoma with placental involvement is exceedingly rare. Although associated with a poor prognosis, we identified two patients who lived beyond the first year of life. Most cases were only detected because a careful histopathological examination of the placenta identified metastases which then prompted the search for a primary tumour. Presentation of a fetus with hydrops and placentomegaly but no other underlying reason should prompt a careful histopathological analysis of the placenta to exclude tumour metastases.