Post-thoracotomy intercostal artery pseudoaneurysm manifesting as a chest wall metastasis

Intercostal artery pseudoaneurysm (IAP) represents an extremely rare vascular abnormality developing after an insult to the vascular wall with blood collection within the vascular wall layers and subsequent dilatation. Treatment options, apart from observation, include embolization, endovascular stenting, and surgical correction. We describe the case of a 73-year-old male patient with colonic adenocarcinoma pulmonary metastasis. Repetitive wedge resections and a right lower lobectomy were performed to remove multiple metastatic lesions. At follow-up assessment, the patient reported localized thoracotomy site pain progressing with time and unresponsive to oral analgesics. Chest computed tomography (CT) revealed a pseudoaneurysm of 4-cm diameter of the right 5^th intercostal artery. The patient underwent embolization of the lumen and was discharged from the hospital after 24 h. Successive CT re-assessment checks were unremarkable.