An intercostal artery aneurysm rupture in a patient with neurofibromatosis type 1-associated gastrointestinal stromal tumor during sunitinib therapy.

Neurofibromatosis type 1 (NF1) is associated with an increased risk of gastrointestinal stromal tumors (GISTs). Vasculopathy, such as aneurysms, is a recognized complication of NF1; however, it is little known among gastroenterologists. We report a 65-year-old woman with NF1 who developed hemorrhagic shock due to rupture of an intercostal artery aneurysm during sunitinib therapy. The patient underwent distal gastrectomy for duodenal GIST at age 49, but later developed hepatic and peritoneal recurrence. Because of failure of imatinib therapy and multiple transarterial embolization procedures, sunitinib therapy was initiated, stabilizing the disease for nine months. During treatment, she developed acute back pain with severe hypertension (220/106 mmHg) and was immediately admitted, where intravenous nicardipine was administered. Despite initial stabilization, the patient abruptly went into shock the following day. Dynamic computed tomography (CT) revealed a massive right hemothorax, posterior mediastinal hematoma, and contrast extravasation from a right intercostal artery aneurysm. Emergency angiography confirmed rupture of the ninth intercostal artery aneurysm measuring 18 mm. Embolization with microcoils achieved complete hemostasis. The patient recovered without sequelae and was discharged on day 34. Through a literature review, we identified 16 cases of intercostal artery aneurysm rupture in NF1. Of these, 11 were treated with embolization, although two experienced rebleeding. Sunitinib inhibits vascular endothelial growth factor signaling, which can induce hypertension and destabilize vascular integrity. Sunitinib therapy in NF1 patients requires strict blood pressure control. Additionally, pre-treatment vascular screening with CT angiography may be warranted.