Three Extremely Rare Findings in the Same Patient: Harlequin Syndrome, Thyrocervical Trunk Aneurysm, and Systemic-Pulmonary Arterio-Arterial Fistula.

Harlequin syndrome is a rare autonomic disorder characterized by unilateral diminished sweating and flushing of the face in response to heat or exercise. Extrinsic ganglion compressions, most of the times by neoplasms, can induce the syndrome. During investigation of a 27-year-old woman presenting Harlequin syndrome with diminished sweating on the left side and flushing of the right half of her face, a left thyrocervical trunk aneurysm was detected by angio-magnetic resonance imaging. Thyrocervical trunk aneurysms are rare, and only a few cases have been reported. Treatment is advised due to possible rupture and airway compression by the resulting hematoma. Endovascular treatment was scheduled. Angiographies revealed bronchial arteries arising from a common trunk at the right thyrocervical trunk and the left bronchial artery was feeding an arterio-arterial fistula to the left pulmonary artery; the left thyrocervical trunk aneurysm was confirmed and an anomalous artery arising from the aneurysm converged to the left pulmonary artery arterio-arterial fistula; the fistula was also supplied by a branch of the left internal mammary artery. The young age and lack of clinical antecedents suggest a congenital etiology for this fistula. The treatment was postponed until cardiopulmonary repercussions of the arterio-arterial fistula could be assessed. Coil embolization of the aneurysm was performed in a second procedure. The fistula was not treated. The patient has been followed up for 12 months without complications.