Thoraco-abdominal fusion of twins is a rare malformation (1/50.000 live births) known as “Thoracopagus sternopagus tetrabrachius”. Most of the therapeutic problems encountered concern the degree of cardiac and hepatic fusion involved and this may be assessed by performing echocardiography, angio-TC and angiocardiography together with the conventional radiology techniques.

Case report. Two month-old ‘conjoined twins’ (Alphonsine Al, and Stephany St) with thoraco-abdominal fusion were admitted to our hospital. Gastrointestinal tract contrastography failed to show any comunication between the twins. Echocardiography showed cardiac fusion at atrial and ventricular level. Al showed a well-formed heart with a small atrial septal defect and mild aortic stenosis, while St showed a common atrium, fused with the left atrium of Al, connected by a common atrioventricular valve with a discordant single ventricle of left type (ventricular L-loop). No evidence of pulmonary trunk was found. Computed tomography and angio-TC confirmed cardiac and hepatic fusion showing a common arterial hepatic circulation. Cardiac catheterization and angiocardiography of Al confirmed a mild aortic stenosis and showed a severe aortic coarctation with the lower part of the body served by artero-arterial anastomoses of St, whose ventriculography showed pulmonary atresia and pulmonary hypovascularity. Arterial oxygenation of both circulations was provided by Al via atrial and ventricular fusion, while peripheral perfusion was mainly due to the systemic circulation of St. In conclusion, echocardiography, angio-TC, and angiography integrate the conventional radiographic techniques and are useful diagnostic tools to clarify the anatomy and/or physiology of thoracopagus twins, and to evaluate the feasibility of their surgical separation.