Even small aneurysms can bleed: a ruptured small idiopathic aneurysm of the internal thoracic artery.

Internal thoracic artery (ITA) aneurysms are rare, but a rupture is potentially fatal. Most cases of ITA aneurysms are iatrogenic, caused by, for instance, previous sternotomy or pacemaker implantation. Other known aetiologies are vasculopathies, either of inflammatory origin or as part of connective tissue disorders like Marfan's syndrome, Ehler-Dahnlos syndrome or neurofibromatosis Type 1. Idiopathic ITA aneurysms are exceedingly scarce. The present case illustrates an unusual scenario, which posed diagnostic challenges, where spontaneous rupture of an idiopathic or possibly very late post-traumatic aneurysm of the left ITA led to a life-threatening bleeding, successfully treated by endovascular coiling with standby preparation for conversion to open surgery. This case demonstrates the importance of the careful interpretation of radiological findings and the significance of multidisciplinary collaboration between radiologist and clinician.