Objective: To describe the presentation and investigation of an unusua
l form of congenital dorsal midline thoracic mass. Results: An infant
born by emergency Caesarean section at 34 weeks gestation was found to
have a large dorsal midline thoracic mass. The infant had normal neur
ological function in all limbs. Radiological investigation showed no a
bnormality in the vertebrae. Ultrasonographic investigation suggested
the mass to consist of subcutaneous oedema. The mass resolved complete
ly within the first 2 weeks. Conclusions: The lesion observed in this
infant represents a very unusual location for a benign condition cause
d by cervical pressure on the presenting fetal part. The use of ultras
onography enabled rapid exclusion of the more common, potentially seri
ous, causes of a congenital midline dorsal thoracic mass.