Congenital tumours are rare. They differ from those tumours occurring in childhood in that their prognosis is generally poor, with some exceptions such as congenital neuroblastoma, hepatoblastoma and retinoblastoma. Congenital neuroblastoma, though histologically malignant, tends to regress spontaneously, while some histologically benign tumours such as teratomas and lymphangiomas may be fatal because of their location and, as they are often very large, may cause mass effect and may prevent normal organ development.

The diagnosis is most often made or suspected during routine prenatal US. The developments in MRI, in particular the fast T2-weighted sequences, now provide radiologists with an imaging tool by means of which the fetus can be imaged without sedation, and good-quality images can be obtained. The large field of view available with MRI allows more detailed estimation of tumour size and extent together with better assessment of the relationship to surrounding structures. Tumour characteristics can also be more accurately assessed, particularly now with the addition of T1-weighted, T2* and diffusion sequences.

The presence of a fetal tumour may create many problems for the obstetricians who provide prenatal care, and an accurate early prenatal diagnosis is very helpful for prenatal counselling. Providing an accurate diagnosis also helps the obstetrician to identify those patients who require only supportive therapy and those who require early intervention. It is also very helpful in that the method of delivery of a fetus with a tumour may require a multidisciplinary approach and thorough advance planning in conjunction with neonatologists, paediatric surgeons and paediatric anaesthetists, such as those fetuses delivered using an ex utero intrapartum treatment (EXIT) procedure.

This minisymposium is therefore timely as it reviews the various congenital tumour types and the current imaging and clinical approaches to their management.