Coarctation-like features from skeletal anomalies: recognising extrinsic compression in fetal echocardiography.

Prenatal diagnosis of coarctation of the aorta (CoA) remains a challenging diagnosis in fetal cardiology. In rare situations, extrinsic compression of the aorta can produce a pseudocoarctation-like appearance, characterised by elongation and kinking of the aorta. This appearance is rarely recognised prenatally and is not well documented. We report a fetus at 24+4 weeks with ventricular disproportion and arch kinking, initially raising suspicion for CoA. Echocardiography demonstrated preserved haemodynamics and no discrete narrowing, but findings were consistent with extrinsic compression of the descending thoracic aorta by a bony spur from thoracic diastematomyelia. Three-dimensional imaging confirmed vertebral anomalies, kyphoscoliosis and tethered cord. These findings indicated coarctation-like features secondary to skeletal anomalies. The pregnancy was terminated, given the guarded prognosis from extensive spinal dysraphism. This case highlights a possible diagnostic pitfall in fetal echocardiography and underscores the importance of systematic evaluation to distinguish extrinsic mimics from true coarctation.