Abstract
BACKGROUND: Klippel-Trenaunay-Weber syndrome (KTW) is a rare congenital vascular disorder associated with venous malformations and an increased risk of thromboembolic complications, including pulmonary embolism. Fewer than 15 cases of pulmonary embolism in patients with KTW syndrome have been reported, highlighting the limited evidence to guide diagnosis and management. CASE SUMMARY: We report the case of a 39-year-old woman with known KTW syndrome who presented with acute hemoptysis and was found to have a massive bilateral pulmonary embolism with saddle involvement. She underwent emergent percutaneous mechanical thrombectomy and inferior vena cava filter, followed by anticoagulation with close multidisciplinary management. DISCUSSION: This case illustrates a rare but severe manifestation of KTW syndrome, emphasizing the dual risk of thrombosis and bleeding that complicates management decisions. TAKE-HOME MESSAGES: KTW syndrome confers a heightened risk of life-threatening thromboembolic events, including pulmonary embolism. When hemoptysis is present, management requires the careful balancing of anticoagulation and bleeding risk, with multidisciplinary coordination.